Cant play AVI files on coby PMP 4330

You could try to convert avi to mp4. You could pick one video converter to do that. And I'd like to recommend Leawo Video converter to you. https://www.leawo.org/tutorial/avi-to-mp4-avidemux-1334.html

There are two fairly common reasons why Windows Media Player (WMP) stops to play AVI files. First is that AVI files are no longer associated with WMP. To fix this, open WMP and press Alt to show the menu. From the Tools menu choose Options... In the window that opens, click the File Types tab (note that this doesn't exist in WMP 12, only in previous versions). Check that Windows video file (.avi) is ticked and, if it isn't, tick it and click OK.

If Windows Media Player still can't play AVI files, you could then try to update your Windows Media Player. Press Alt key to show the menu if you can't see it and then choose "Help > Check for updates..." and follow the on-screen instructions.
Or you can download a free AVI player program which can support AVI format, such as Leawo Blu-ray Player which is a free player program and is a region free Blu-ray and DVD player.

As I know, coby player supports mp4 video. You might convert the AVI video to MP4 video for a try, it should fix your problem. If you don't know how to convert video, I think this step by step direction would help you a lot.

How to convert AVI MP4 WMV MKV FLV MPG and YouTube video

Technically Coby PMP-4330 is able to play ASF, AVI, MPEG-4, Motion JPEG, WMV and XviD video formats. If error occurs when you try to play AVI on the device, there should be something wrong with the parameters. Try this video converter on your computer to adjust the output video format and parameters.
http://www.leawo.org/video-converter/

Avi format itself conatins many encoding formats . usually avi players support Xvid encoderd videos . u try to conver the video to xvid fmovie format ( .avi) with some video converters and try . ( i prefer xilisoft video conavrter ) . try and reply me