Problem syncing apps back to iPad on iOS 4.2.1
I have a strange problem syncing apps back to my iPad which I (after several unsuccessful efforts) upgraded to iOS 4.2.1 yesterday.
Well for starters when I plugged my iPad into my laptop (Windows 7) and clicked the update button in iTunes, it would start the update process but would remain in the "verifying update with Apple" stage rather long and eventually give an error saying "your firmware could not be updated" leaving my iPad in DFU mode. It didn't even give a reason as to why it couldn't update my firmware.
Anyway, I had to restore my iPad to get it running again (and this again wasn't as straightforward as it should have been). It kept "verifying restore with Apple" and almost always gave an error. Finally I somehow managed to restore my iPad but luckily I had backed up all my apps and books to iTunes before all of this.
However I didn't restore my old apps and books just yet, I tried to update my firmware once again - but it didn't work again! Even on my completely restored iPad! And I was stuck in the DFU mode once more, so I had to restore again. But this time something strange happened - after completing the restore process my iPad restarted and it was somehow running iOS 4.2.1!
Anyway, atleast I had managed to get iOS 4.2.1 on my iPad, but I still didn't have any of my old apps or books. So I plugged it into my laptop and tried to sync my old apps and books to my iPad through iTunes. The books went through just fine, but only the apps that can be obtained for free in the App Store got synced back to my iPad! The vast majority of apps (ie. the paid apps) simply didn't get synced to my iPad (iTunes just gave an error for each of these apps, not stating what exactly the problem is).
Does anyone have a clue how I can sync the paid apps from my iTunes to my iPad?! I know it should be straightforward, but each time I try it, it gives me an error.
Thanks in advance!