Nested Album Error

I've just lost one of my nested albums, and I can't figure out what the problem is. There is nothing special about this album other than the fact that it was the largest and most popular one on my site. No other albums have been affected. There is no thumbnail for the gallery any more, it says it has an "Untitled" name, and displays this error below. If you try to access the gallery it just returns you to the main gallery page.

Changed:
Warning: stat(): Stat failed for /home/gtplanet/public_html/gallery/photos//album.dat (errno=2 - No such file or directory) in /home/gtplanet/public_html/gallery/platform/fs_unix.php on line 79
12/31/69.
Contains: 0 items.

I noticed the two slashes befor album.dat, could that be the problem? How could I change it? And why did it change in the first place? I never made any changes when it suddently broke. You can see this error for yourself at http://www.gtplanet.net/gallery/gt4. Thanks for your help!

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Give us your Gallery/webserver information to get a faster answer.
Get this information from the PHP diagnostic (in the configuration wizard).
Gallery URL (optional but very useful): http://www.gtplanet.net/gallery/
Gallery version: 1.4.3-pl2
Apache version: 1.3.31
PHP version (don't just say PHP 4, please): 4.3.7
Graphics Toolkit: NetPBM
Operating system: RedHat Fedora
Web browser/version (if applicable): IE6