Cannot log-in: problem with .users/userdb.dat.lock or fs_uni

I am not quite sure where the problem lies. Whether I need to change the premissions on fs_unix.php (and if so, to what) or if there is something wrong with userdb.dat.lock? I looked through all the help files and forum and was not able to locate any threads addressing this error.. if there is, would some one be so kind as to point me in the right direction. Thank you in advance for any help you can provide me with. :smile:

Here is the message I receive:

Warning: fopen("/home/username/public_html/blah/photos/albums/.users/userdb.dat.lock", "a+") - Permission denied in /home/username/public_html/blah/photos/platform/fs_unix.php on line 53
Error: Could not open lock file (/home/username/public_html/blah/photos/albums/.users/userdb.dat.lock)!