MT Import: Missing Posts

In testing WP (1.2) , I’ve imported nearly 3000 entries and comments from MT. So far, it’s looking like I’m missing about 50 (ish) posts. This isn’t really a big deal but, using mod_rewrite I’ve got my URL’s exactly the same as they were. However, at some point, they stop matching up as the missing posts start adding up.
Is it possible that some bad HTML in old posts caused them to get borked during the import?
If so, what would be a good way to go through all of that data and “scrub” it for that sort of thing?
I did use mozilla to do the export from MT.