Trouble uploading photos version 3.4 (file could not be moved)

for WP I’ve been able to upload photos fine even with version 3.4 despite people having trouble with it. Now a few days ago I can’t upload photos and I get an error message that says:

(file name).JPG has failed to upload due to an error
The uploaded file could not be moved to /home/(our previous site name)/(previous site name).com/NSM/wp-content/uploads/2012/09

I believe the problem has something to do with the FTP, permissions, and some coding on WP. Can anyone help? Do I need to upgrade/downgrade?? Any advice would be greatly appreciated. Thanks