USB File Transfer difficult on Cy10.2 ATT GS2 Skyrocket
This doesn't directly answer your question, but you could use an FTP app instead, an app which runs an FTP server on your phone that you then connect to over your local network using a client such as FileZilla on your desktop machine?

(This is how I transfer files to and from my own Android device, the USB is just too slow and unreliable)