You can [...] allow raw html
From the manual (
http://www.mediawiki.org/wiki/Manual:$wgRawHtml):
This is very dangerous on a publicly editable site, so
you can't enable
it unless you've restricted editing to trusted users only
However, the SecureHTML extension might solve this problem:
http://www.mediawiki.org/wiki/Extension:SecureHTML
As for the original issue:
The table tags TR and TD dont get parsed in my wiki.
I thought table tags were okay - at least they work on our wiki.
Which version of MediaWiki are you using?
-- F.