iPhone 4 ' iTunes Sync 'app name' failed to install

I had a similar issue with my iPhone 4 (iOS 5.1.1). When I updated to 5.1.1, I did so via the "Restore" function of iTunes, and I chose to "setup as a new iPhone" instead of restoring from a previous backup. Suddenly any apps that I synced from my iTunes library didn't show up on my springboard after the sync completed and I got multiple errors "iTunes Sync (app name) failed to install". Being cruched for time, I'd just eject my phone and download the apps on the fly in the car or when I had the time as I went about my day but it started getting frustrating having to reinstall the exact same apps every day because when I plugged my phone in at night to charge and sync wirelessly, iTunes would remove the apps I downloaded and give me those errors again in the morning about apps failing to install. From what I can tell, it seems to be something with the iTunes DRM coding from the app you downloaded before the last "setup as a new iPhone" restore and the coding your iPhone is using as that "new iPhone". I can offer a "work around" that works but it's not by any means a solution because you have to do it with each and every app instead of just instituting some kind of software update fix. My workaround is, while your iPhone/iPad/iPod Touch or whatever you've "restored as new iDevice" is connected to iTunes, delete the apps you're having issues syncing, move them to the trash, and download them new from the iTunes App Store. After they've been downloaded, they'll sync everytime no matter if you're checking them in a list or just dropping them on the iPhone in the iTunes sidebar. Until there's some kind of software update to address the "DRM coding" issue between old apps downloaded in iTunes or on other iDevices and syncing them with a "new iDevice" it's the best I can offer. Good luck.