A friend of mine was having this problem and found a thread discussing it here..

Ok so I first saw an issue with this after upgrading to the latest firmware on my iPhone. In the past I could update my apps through my iphone then transfer to iTunes later now I cannot update AND it tells me to go to iTunes and update there.

1. I get the error above, 0xE800002E, when I try and update apps through iTunes as instructed.
2. The only WORKAROUND I have found is to remove app from iPhone and LOSE all Data.
3. then resynce from iTunes with new app.

I lost all my saved games for Vay and All my budget info for August this is a horrible situation. Does any one have the official line from Apple on this as to a fix …..a quick search on Google and you will find I am NOT the only one with this error. Also my phone is 100% legit NO JAILBREAKING.

After some searching, he found a soution from imyourdaddy.  Link to the orginal here..

You can try this to get those Apps working again:

-delete applications from iphone
-turn iphone off then back on
-deauthorize computer in itunes (under store), close down itunes
-open itunes back up, authorize computer (under store in itunes)
-plug in iphone to sync apps over

This worked for me. If it doesn’t work you can try deleting the Apps in iTunes as well, then re-downloading them in iTunes, then syncing the phone. No need to run a Restore. 

Hope this helps you if you have this problem.