After reading your reply, I just now popped over to IE 5.5. Wow. It looks TOTALLY different in IE than it does in Opera. In IE there are light blue bars holding the post info, a paragraph break, then the post, then the navigation buttons centered after a paragraph break.
In Opera the first line of the post is right under the "to XXXXX" line, there is no blue bar, and the navigation buttons are left justified.
In IE the text in the blue bars is way small, but I can deal with that.
I guess Opera isn't able to deal with whatever kind of coding you're using.