Currently Being ModeratedJan 23, 2013 12:51 PM (in response to Carolyn Samit)
It solved my problem too! Late 2012 2.9 GHz Core i5 iMac 8 GB RAM, OS 10.8.2. Kirk at BusyCal referencedthis site. I only had to delete ~/Library/Caches/com.apple.appstore/Cache.db and ~/Library/Preferences/ com.apple.appstore.plist—and then restart.
One should note her ~/Library caution and the required restart when finished.