Originally Posted by jkbbna
According to Amazon's Manmeet you have to be running Android 3.7 or higher.
Do you mean 2.3.7? Or really 3.7 (Honeycomb)?
If you are rooted and have a Titanium Backup of it you can restore. Or now may be the time to install a Gingerbread ROM.
I am guessing you had the app through the Amazon Appstore. In my experience witht he Optimus V, if an app update through the Play Store makes it incompatible it won't let you update.