iphone 3gs wont restore error 21

Hi

tonight I updated itunes to the latest version 9.2, then I check to see whether my actual iphone software needed to be updated. it said the new version available was the 4 one.

once it went to finish installing it said it couldn't be installed properly due to error 21. so after several times trying to get it to work I decided to restore.

but now it wont even restore cause the same error 21 keeps coming up. once I clicked restore it looks like its about to finish but then the error comes up then stops, now my phone is stuck with the itunes logo with the usb

cant get onto my phone at all and cant restore it dont know what to do, can someone help me out please or if anyone else had this problem could they advise me what they done

thanks
lindsay

Message was edited by: itslindsay