[wot-Mike]

I think you did everything right:
in chatredirect change:
chat.php?setwidth=955&setheight=330

to something like:
chat.php?setwidth=925&setheight=330

Don't know if the size is right, it takes some experimenting.

(Do NOT use percentages! The whole reason for this setsize construction is because IE6 has a bug in it's java support, which effectively kills a chat room re-load (the first load is fine, and reload fails). Chris from raidersoft support found this out for me )

chat.php the array should contain the same values as the set"size" from the javascript bit.

Now you've all done that, meaning that the chat is cached somewhere. I ran into the same problem.
Either empty your browsers cache,
or (in my case):
PHP Accelerator had cached chat.php, but failed to see any subsequent minor changes. I had to stop apache, clear out the PHP Accelerator cache, end start apache again

Hope that helps