Whenever I try to download or update an app from the marketplace, I get an error message saying "error: cannot install on USB device or SD card" I don't believe it is due to memory issues, since I have 5.26 GB available on the SD card and 6.02 GB available on the phone. Is there any way to fix this problem without having to do a factory reset and losing the apps I have already downloaded (including ones that were free once but no longer are)? Is anyone else having this issue? Please help!