showthread width needs fixing

[maryx]

Attached is a snapshot of the showthread page (I think that's what it's called - it has the Title/Thread Starter heading. You can see that the width of the left side block, (the list of threads) is too narrow. The rightside block is where we run custom ads, that is showing up just right.

Where do I go, exactly, to change width of the showthread block? The other pages are just fine, the forum front page and the actual posts are the correct width. This is the only class of page that is too narrow.

Thanks!!!