Finally there is a complete solution for an installation error in samsung galaxy ace and pop phones. The error resulted in unsuccessful installation of apps to SD card or USB storage, showing an error, "Couldn't install on USB storage or SD card".
The solution is to update the phone to the latest Gingerbread update. Before the update I was getting the same error at least once in two installations. But after the aforementioned update its completely ok. So I suggest you to do the update to permanently escape from the error.
