is there anyway to move the posts as well?
that is why he asked you twice , exactly what you wanted to do.
if you want to move the posts, then you also have to move the forums, categories, etc, etc.
just backup your complete database and restore it over your new one.
then you will have your members, posts, forums, etc, etc.
anything that the old MODs put in the database will not hurt anything to just leave alone.