App info is currently processing and/or the app is not yet fully available for sale on the US App Store.
...and it is pointless. The button to free memory has been removed (not that is has worked since iOS 4 anyway.) EDIT: I might take that back. It seems as though it clears memory automatically. More testing is required.
Yes, that works quite well. I forced the memory full and it cleared it. Nicely done. Grab it quick before Apple changes it's policy on memory freeing apps again.