backup up Ipod Touch on new computer

Welcome to the discussions,
is your new computer authorized in the Store menu in iTunes? http://support.apple.com/kb/HT1420
Any restrictions set on the ipod for app-installation in Settings/General/Restrictions?
To transfer your data to a new computer, back up manually by right clicking on your ipod in the device list and choosing "backup". Transfer your purchases the same way, set up at least one contact and event on the new computer, to be able to merge data after your ipod got erased during the first sync. Use the manual backup to restore from and all data and settings should be back again.
More info here: http://support.apple.com/kb/HT4137 and here http://support.apple.com/kb/HT1766

or another method is tocopy the itunes files and place them in plaace of the old itunes.
only a suggestion.

hope i helped.

Based on other users experiences, you can't backup an iDevice to another computer. It has to be its syncing computer. Otherwise it would be too easy to steal info from a lost iDevice.

lllaass wrote:
... Otherwise it would be too easy to steal info from a lost iDevice.

Correct, you'll have to authorize this computer and use the same iTunes account again, to be able to use the apps and play the bought media from the iTunes Store.

Just download Copytrans, install it on your pc, run it, connect your ipod, select your music and videos and click on the "Backup to iTunes" button. it'll copy your entire ipod library back to your PC.
The following tutorial of [how to transfer iPod touch to new computer|http://www.softwarebbs.com/wiki/How to_transfer_or_sync_files_from_iPod_toPC] will give you a clear and satisfying answer.
Cheers.