Categories Error

I’m getting this warning:
Warning: Invalid argument supplied for foreach() in /home/wrywrite/public_html/photodog/wp/wp-includes/template-functions-category.php on line 304
on my page and don’t know what to do about correcting it. Is it because I’m using a template (DOTS) written for 1.0.1 while running WordPress 1.2, or something else?
Hope someone can lead me in the right direction.
My URL is: https://photodog.wrywriter.com/wp/index.php