I really need this converter too... I tried it at least 10 times and was able to fix some errors I had at frist (by changing some settings). But still I can't fix what follows:
1) private messages. They were succesfully converted. I checked out my smf pm table, and they all are there... but still, whenever I login, my smf forum keep on displaying "you've 5 new messages on 40" or something like that, but the box is empty... so I think the problem is not related to the converter itself, but there's something wrong when displaying the forum.
2) Attachments. Succesfully converted, but not displayed as clickable thumbnails as it should be (image attachments, I mean). It's not a matter of GD libraries, because I opened a new topic (after the conversion) and uploaded an image attachment, that was displayed as clickable thumbnail.
3) Avatars. This is weird, but it seems that I can't convert them. Avatars uploaded on other sites are succesfully converted, but the ones uploaded on my web space are not displayed when browsing topics... and if I go to my edit profile area, avatar setting, I can see my avatar!!
4) Signatures. Some tags are not proprerly converted, and the signatures are all messed up, even some bbcode.