Hey there,
Just wanted to give you an update and say you were completely right...

After actually opening up the Database tables I found that it had assigned several different variations to a persons name, it seems depending on how they had been logged into the old board when the specific post was made.
ex.
ChuqNorriz
chuqnorriz
Chuqnorriz
Any posts from the first spelling worked great, but any from the other two spellings showed as guests (or member number -1).
I was able to go directly into the Messages table and re-assign the errant "guest" posts back to the actualy member, but It was done one message at a time.
Forgive me for my newness to Databases, but I'm going to be converting another board very similar soon and I was wondering if there might be a way for me to get ahead of the game and fix this prior to the conversion.
The Original board is on Yabb Gold SP1, and I am hosting it here at my house so I have complete access to all the files.
Also Dani if your still having a problem with this send me some E-Mail and I'll give you the exact Tables and Colums I changes to fix this.
Also if anyone has a suggestion as to how to fix this post conversion any faster then one message at a time I'd love to hear it.
Thanks again,
Russ