Warning: Division by zero in /var/www/dissus/gallery/albums.

I keep getting this message: Warning: Division by zero in /var/www/dissus/gallery/albums.php on line 68

and I havent been able to figure out what the problem is. Any help would be great. Thanks
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The following information is required to get an answer:
Get this information from the PHP diagnostic (in the configuration wizard).
Gallery URL (optional but very useful): www.diss.us
Gallery version: 1.5
Apache version: Apache/1.3.27
PHP version (don't just say PHP 4, please): PHP Version 4.3.11
Graphics Toolkit:
Operating system: Red-Hat/Linux
Web browser/version (if applicable):