Hi,
Open a Finder window. Select your Home folder in the Sidebar on the left. Now open the Library folder then the Caches folder then the com.apple.appstore folder. Move the Cache.db file to the Trash.
From the same Library folder open the Preferences folder. Move the com.apple.appstore.plist and the com.apple.storeagent.plist files to the Trash.
Now open the Cookies folder from the same LIbrary folder. Move the com.apple.appstore.plist file from the Cookies folder to the Trash.
Restart your Mac. Try launching the app store.
If that doesn't help, try the suggestion by sgginc on this thread regarding Safe Boot.
http://discussions.apple.com/thread.jspa?messageID=13226438�
Carolyn 🙂