I just noticed this issue moments ago. Neal-UK, you'd need to edit the 2 files that The Geek mentioned and change the following:
In "vbplaza_postdata_delete.php", remove the " ` " from the following line so that it looks like this:
Code:
user." . $vbulletin->options['vbbux_pointsfield'] . " = user." . $vbulletin->options['vbbux_pointsfield'] . " + post.vbbux
In "vbplaza_threaddata_delete", do the same as above, as well as changing "THREADPREFIX" to "THREAD_PREFIX".