In my chat box the messages i send to my friends they don't receive it but when i send them same messages through messages they receive it

Is it just facebook or your internet connection ??..
The Facebook Chat feature allows you to send and receive messages in real time with friends who are online.
Your chat box reveals a list of available friends you can chat with by clicking their names.
For those times when you're not up for chatting, you can choose from several different privacy options, including disconnecting Facebook Chat.
You can opt to disconnect it completely, or just partially allowing chat availability for certain people and not others.
You can reconnect in a few quick steps.
Facebook Chat Availability

Your Facebook Chat availability determines how you appear in your friends' chat lists.
When you're logged in to your Facebook account, your name appears in the chat sidebars of any friends who are currently logged in.
When you set your chat preference to available, a green box appears next to your name.
When you're available, but idle, a grey moon appears next to your name.
When you're unavailable, your name appears without an icon.

Adjusting Chat Availability
Adjust your chat availability to control the visibility of your name in friends' chat lists.
Sign in to your Facebook account and click the "Chat" box in the lower right corner of any page to open your chat list.
Click the "Options" icon in the upper right corner of the box.
Click "Go Offline" to disconnect your chat availability.
If you're using the Facebook Chat sidebar, click the "Options" icon in the upper right corner of the box. Click the "Chat" box to open the sidebar if it isn't showing up on your home page.
Click the "Available to Chat" option to delete the check mark, making yourself invisible and unavailable to chat. Click the "Limit Availability" option and use the resulting pop-up to choose which friend lists you wish to remain visible to. This allows you to chat with some friends without others knowing you're logged on.
Disconnected Facebook Chat
Once you disconnect Facebook Chat or limit your chat availability, your online presence will be invisible to other users.
You can still browse the Facebook site as you would normally.
The appearance of your chat list won't be altered by your availability; you'll still be able to see which of your friends are online and available to chat.
That is, as long as their chat availability isn't hidden or disconnected.

Your Chat Messages

If a friend attempts to message while your Facebook Chat is disconnected, the message will be delivered to your Facebook inbox.
You'll receive an on-site notification, as well as text or email notifications if you're set up for that, alerting you that you have a new message in your inbox.
Click the "Message" icon that appears in the upper left corner of any page upon signing in to your Facebook account.
Any new messages will appear in the drop-down list. Click the "See All Messages" link at the bottom of the box to access your inbox and respond to any messages.

http://www.facebook.com/help/?topic=chat

Use Facebook, Twitter, Gmail Chat. For whatever reason you're using Yahoo messenger, if you're too attached to it to use something else, try disconnecting and reconnecting, or send a different type of message, or try to connect with a video chat or phone call through Yahoo.

with an MMS-enabled phone you can:
Take digital photographs and store photographs on the Internet Send and receive full colour pictures Send and receive voice clips Add a text message to your picture Purchase pictures and sounds from the Internet Have enhanced polyphonic ringtones
MMS runs over GPRS. You normally need to subscribe to a GPRS tariff, and have 'Media Messaging' enabled by your network operator. You will need a phone handset that supports the MMS service - If you receive an MMS message and don't have a suitable handset or GPRS service, you'll receive a standard SMS text message, and will be able to view the message at the web address included with the text message.

hi alan. the error you received might be due to network error.

Facebook affords its users several means of communicating with one another, from public posts made to the collective News Feed and individual users' Walls to direct, private messages. Facebook also allows for real-time chat communication between users who are both online -- this doesn't, however, include an option to chat using video as of this writing.

How Facebook Chat Works

Facebook chat functions much in the same way as standalone chat clients, such as AOL Instant Messenger and Windows Live Messenger. To chat with another user on Facebook, he must be one of your contacts and also be online. Two categories of online friends exist: Available and Idle. Available friends, which appear at the top of your chat list and have green dots next to their names, are actively using the site and, therefore, more likely to be available for chat. Idle users are not actively using Facebook, and although they're signed in, they may not be at their computer to chat.
Chat Capabilities

Facebook Chat is simple and, as of this writing, permits you only to send text in most cases. The one exception is in the case of emoticons. If you type ":)", for example, a yellow smiley face appears. Beyond this, Facebook Chat's list of features is rather limited. If you don't want to chat within the main Facebook interface, you can pop out the chat box and continue your conversation in a separate window. You can also make yourself go offline if you don't wish to chat with others or to let them chat with you.
Links and Videos

Although you may direct others to pictures, videos and other multimedia within chat -- namely, via text links to the URLs at which they're hosted -- it's not possible to embed images and videos themselves within a chat message. Furthermore, Facebook Chat isn't capable of video chatting, such as programs like Skype and Windows Live Messenger. If you want to communicate with one of your Facebook friends via video message, you won't be able to do so using Facebook Chat.
Skype Workaround

One potential workaround to Facebook not having video chat among its features is using Skype's Import Contacts feature. In addition to being able to import contacts from email clients such as MSN Hotmail and Gmail, you can enter your Facebook credentials and cross-reference your contact list to see which of your friends are also using Skype. After you've done this, use Skype to make free video calls with your Facebook friends who use the program.

I hope you find it very helpful. Thank you for using fixya.com

Hi there, I've been experiencing the same issue with Facebook. Here's what you can do. instead of chatting through the chatbox, hit MESSAGES then use it instead on chat box. You can chat from there as long as your friend is online. Maybe there is a bug on Facebook.
Good luck!

Simply because he/she is offline & using " i'm on mobile " (usually stated under the user's icon), which means he/she will not receive any messages through PC/laptop but via mobile phone. Still, you can send them messages but in very limited ways or tries. In this case, it is normal. So, don't worry, nothing went wrong, you just have to wait until he/she is back online.
**NOTES: Remember, when using " i'm on mobile " or replying chats via mobile phones, credits will be deducted from your mobile account.

You should check this facebook page:
http://www.facebook.com/help/?faq=19779

there you have to delete from your registry another folder that is not needed from your application then you are going to delete it..just follow my instruction if you have using another operating system then explore for it this is almost the same...for windows xp,2000,NT etc; other OS this direction may vary

first click on start>Run>type "regedit"find HKEY_CURRENT_USET>Software>Microsoft>Windows>CurrentVersion>Internet Settings>Zones.delete key or zone names as for example "?" or a square like you could seebut except keys 0,1,2,3 and forPLEASE DON'T DELETE keys 0,1,2,3 and 4.
if it doesn't work jus simply restart your YM applicationor maybe your PC.. and there you go..If this doesn't work just send me mail [email protected]'m glad to help... if its much helpful pls send me also a mail or just post it in my fb Account..
microsoft>windows.currentversion>internet settings>[email protected] - fb account.. thanks everyone

hi, Sounds like a Scripting error. I'm giving you a Help Link to follow:
http://help.yahoo.com/kb/index?y=PROD_MSNG&page=content&id=SLN40&impressions=false&actp=RECENT

Also make sure you have the latest Flash player and Java installed.
http://www.adobe.com/shockwave/
http://www.java.com/en/download/index.jsp

After Updating, check that you do not have Old Versions of Flash Player, Shock Wave player and Java ...this causes problems.
click --- Start/Control Panel/ Programs
?Delete the Old Versions First................

Good Luck to You