First I Googled the problem and found this discussion on the Apple support forums. So I have tried:
- Authorize and deauthorize the computer
- Delete and reinstall an application
- Reset the iPhone
- Delete all the applications on the iPhone
- Delete an app from iPhone and iTunes. Then download the application again and reinstall.
I am trying the install from scratch option at the moment. Tried the delete all the applications from the phone option and that didn't work. I will keep you updated on my progress finding a fix.
It is pretty ironic that after I start a web log devoted to iPhone apps, my iPhone can no longer run any apps. lol.
Update: Apple Support found a solution for me.