I can't thread my bobbin. I get a error on the number guide and it is 88. so what is wrong with it not working.

Sometimes you can search for an error code:

Make Model error code

Also, the troubleshooting section may list error codes.

Turn your machine off and leave it off. Remove all bobbins - in the machine & from the pin. Remove all thread - from threaded machine and bobbin thread path. Clip the machine thread at the spool and pull the needle thread towards yourself. Clip bobbin thread at spool and close to bobbin, then pull towards you through thread guides. This keeps the tension where it belongs. Move the bobbin winding shaft from normal sewing back to winding bobbin a couple times. It should click in place when moved to the winding position. Check to see if there is any thread that has slipped under the bottom of the bobbin and wound itself around & under the bottom of the shaft. Carefully unwind to clear. If the shaft does not easily move back to the sewing position it is probably stuck in the winding position. Don't force it, but try to get it out of the winding position. Leave it to the left in the normal sewing position (unclicked). Check to see if there is any thread caught anywhere along the path from spool to the winding pin. Pay close attention to the first thread guide and the two discs the thread slips between that control tension. Hand wind the wheel on the right towards you to raise and lower the needle a couple of times. Stop with needle in highest position. Do NOT wind hand wheel backwards (away from you). Make sure the bobbin pin is not in the winding position. Now turn on your machine. Needle should jump to default position. Move the stitch length and stitch width guides to the far right, then far left, to attain the green lights. Press the reverse stitch button to raise lower and raise the needle. It will stop in the highest position. If you still have the error code - make sure the bobbin winding pin is NOT in the winding position. Remove the needle. Lower the presser foot and run the machine without any thread a bit. If the needle bar does not go up and down most likely the bobbin pin is stuck in the winding position. If the code has cleared use your manual to carefully wind a new bobbin. Make sure you are using a 15J bobbin which this machine requires. It will not work with just any bobbin. Next, raise the presser foot then carefully thread the machine. If you don't have a manual you can download one from the Singer website. You might consider cleaning the entire machine paying special attention to the hook area and feed dogs while the power is off. If you find a lot of lint do this more frequently to prevent buildup. Take special care when replacing the bobbin care. Hope this helps. If not call Singer. It may take some time but you should be able to reach someone to help you troubleshoot. If this is an older machine I recommend taking it for repair yourself instead of sending to Singer

reference: http://www.amazon.com/Singer-7466-Electronic-Sewing-Machine/forum/Fx3BSOY0VA78VQ4/-/1?_encoding=UTF8&asin=B000B91B3K

try adjusting the top thread tension-one number or letter less, then
sew on a piece of the scrap fabric if you have any. to see if that helps
try changing the needle
make sure the bobbin is turned the right way in the bobbin case, I
know this may sound crazy but it can hinder the sewing, I was sewing
a skirt the other night & I turned the bobbin the wrong way & inserted
the bobbin into the bobbin case & it didn't work good,, I took the bobbin
out of the bobbin case & had multiple threads. so I had to clean the mess up & turn the bobbin the opposite way & the machine worked
just fine

here are my suggestions
change the needle--make sure it's inserted correctly in the needle
holder
make sure it's the right needle for the fabric
rethread the machine top & bobbin --use every thread guide
clean under the needle plate & in the bobbin area for lint
make sure the thread has not come off the thread take up lever
make sure the correctly foot is on the machine when sewing
if the suggestions don't help then it would be a good idea to have
the machine checked

here's a free downloadable downloadable manual
http://www.singerco.com/uploads/download/1197_7444engfrespa77250.pdf

The biggest problem most people face when having troubles pull the bobbin thread up is one of the following.

Wrong needle size (or broken/bent or otherwise damaged needle)
Needle is not fully set into the needle bar.
Needle is not correctly oriented.

Pulling up the bobbin thread is a simple matter of threading the upper thread, and inserting the bobbin with about 6 inches hanging loose. Grasp the top thread lightly.... turn the wheel counter clockwise one full revolution (the needle will go down and back up.) Just pull the top thread slightly and you should see the loop come through the throat plate. Use something like your scissor point to swipe under the presser foot to help retrieve the bobbin thread.

What is the model of your machine?

Needle breaks
1.the needle is damaged
2.the needle is not correctly inserted
3.wrong size needle for the fabric
4.the wrong foot is attached
5.the needle clamp screw is loose
6. Top tension is too tight--loosen off one letter or number till the stitch
looks normal
7.make sure that every thread guide is used when winding the
bobbin,, so that the bobbin will wind tightly, if this doesn't help,,
then it's possible that the bobbin winder needs adjustment,, it needs
to be taken to a sewing machine shop

the thread guide & the bobbin spindle need to be check to see if there
is something wrong or just needs to be adjusted

I have never known a sewer that hasn't experienced this before. First: make sure the upper thread is correctly threaded through the tension disks, take up lever, and thread guides. Sometimes, just missing one little thread guide makes everything mess up!. Next, make sure the groove on the needle is FACING YOU. The groove is actually a thread guide as well and if the needle is in backwards, it will cause stitch problems. Then, be sure the bobbin is inserted the right way. Your manual should show you how the thread should come off the bobbin (clockwise or counterclockwise). I have been sewing for over 50 years and there are days when I'm so eager to finish my "creation" I plop the bobbin in going the wrong direction and wonder what's wrong with my machine. While you're checking all this, be sure and use your machine brush to remove all lint in the bobbin case and between the feed dogs. Dust in the bed can cause stitches to mess up! I hope this helps. If it does, please come back and rate my suggestion!

when the thread is on the spool pin
1.guide the thread around the bobbin winder thread guide
2.insert the thread through the hole on the bobbin, threading from the inside to the outside
put the the bobbin spindle
3.push the bobbin winder spindle to the right (if you have a electronic machine the LED display
will show SP)
4.depress the foot control, when the bobbin is fully wound, stop it, & push the bobbin spindle to the left, cut the thread & remove it from the spindle