Today must be national "IE 6 Is A Piece Of Dog Crap" day...
It looks like this is hooking mouseover for all of the rows and cells in the table in addition to the table itself. Grr. To make this work the way you would intuitively think it should, (in IE 6 of course) add a check for the target's tag name to make sure that you are only dealing with the element you want to be.
Thought I'd share. If I post another blog about IE 6 today, I'll probably be too hung over tomorrow to post anything.