Part of the problem may be that IDs have to be unique on a page. It appears that you're trying to have a <td id="td"> for each row in your forumhome table.
Put the {background: url(forumsprite.png) no-repeat top left;} into each of the class definitions and eliminate the #td selector altogether.
You might also try putting some content into the td— like a Table cells act weirdly when they are empty.
--don
|