Hmmm, my vers of vbull is about 2 years old and I can delete a user and all his posts using the control panel... what are we missing?
Users -> Search for Users -> enter Username -> Exact Match
drop down: Quick User Links [Delete User]
"If you want to prune all the user's messages first, please click here" - click on that and the msgs are gone, then you can continue to delete the user if you wish...