@gray: good for you that you have a work around! I don't. If I use the method of deleting all apps from iTunes and iPhone and then sync, I'm having a Groundhog Day all over again. After resyncing I download an app again, sync it, and then get the error again. The other way around: after I deleted all apps on iPhone and iTunes, disable syncing apps in iTunes, buy the same app again through the iPhone, download it since I own it, I get the error that I can't use the app yet, but I should sync it with iTunes first. If I do that, I get the Error 0xE8000002E error again.
This is frustrating. I had six apps which I used very often. Basically, I can't install any app anymore although I paid for 10 of them. Any suggestions?
This is what I wound up doing. I can't find the direct link to the site that had the instructions, so I'm recalling by memory.
Plug in iPhone.
While it's plugged in, hold down the power and home keys for at least 6 seconds. This will cause iTunes to detect an iPhone in restore mode.
Release the power button after six seconds (and after iTunes has detected restore mode) but keep the home button depressed for 10 seconds. iTunes will then walk you through a firmware restore. This resets your firmware to 2.1 (or whatever the most recent version of the firmware is that you have). This takes about 5-10 minutes.
Once your iPhone is restored to its empty state, set up the iPhone as a new phone, not as a restore. This will cause iTunes to reinstall all the apps you have downloaded (and paid for) onto the iPhone. You will lose all your settings, data, and music/vids/podcasts on the iPhone. All of those can be re-synced. You will not have to reset your phone number or anything else.
This is a painful process, especially if you have a lot of apps that store data on the iPhone, so I don't recommend it for everyone. Also, after I did it, I started getting a different error every time I sync (a dataclass initialization error of some type that annoys me but doesn't seem to impact the syncing itself).
It turned out that I had an app update to apply so I didn't download the update until after I'd gone through the process above. After I got everything set up, I downloaded the app update and applied it successfully without getting the 0xE800002E error.
If my directions are unclear, google the error code and you should be able to find the web site I mention above.
Good luck. Hopefully Apple fixes this stupid error in its next update. Doubtful, but I hold out hope.