Even I can't change the filename, it'll break that database. You should however be able to change the title and things like location (BTW, is anyone else adding locations to their photos??).
If you're at the top level of your member gallery, let's say "Home > Member galleries > skully", you should see a EDIT FILES button next to each gallery. Do you see this on your screen? THis is where you make changes.
Let me know if you still need help, I'm happy to help.