OK, I just fixed the problem. This might work for you, but you will lose all settings and saved games, scores, etc.
1. Backup everything.
2. Connect your ipod to itunes. Under the devices menu click on your ipod.
3. Click Restore. Allow the restore to run.
4. When the restore is finished, it will ask you if you want to restore a backup. *_Do not restore! Choose to set up as a new ipod._*
5. Once setup has completed, click the applications tab and select the apps you want to sync. I didn't have to, but some users said it may ask you to reauthorize your computer at this time. Once you have selected what you want, sync it back on to your ipod.
This fixed it for me. *Unfortunately, you lose all your settings and saved games in the process*. I'm not an ipod guru, *so if someone knows how to restore just those items*, let me know.
If you try to restore from a backup, the apps will cease working again. I'm not sure what will happen if you try to restore from a backup before the issue arose. Has anyone tried this?
And yes, this issue is caused because of the Fairplay DRM breaking. I know the subject has been beaten to death like a dead horse, but it gives me an excuse to rant for a moment on why DRM is so utterly useless. It would be one thing if the DRM was actually thwarting piracy, but I can guarantee that every single one of the apps on my ipod is freely available for downloading on jailbroken ipods and iphones. So the only thing the DRM has actually done here is caused a massive headache for those of us that legitimately purchased these apps. One of these days companies might figure out that they shouldn't treat paying customers like criminals. Can you imagine if the actual retail world worked like this? Every time you put on a shirt you are first frisked by a guard and asked to provide proof of purchase of the shirt. Don't have your receipt? Can't read it anymore? Then we are going to rip the sleeves off of the shirt and give you the finger.
It sounds extreme, but that's pretty much how DRM works.