Hi,
how about doing the following:
PHP Code:
$userkills = DBsite ->("Select userid from userfield");
while ($userkill=$DB_site->fetch_array($userkills))
{
DBsite->("DELETE from userfield where userid='$userkill[userid]'");
}
NO WARRANTY and i have no idea if this will work but this is how i would try it first. My suggestion, install a new forum on a testserver and test this out BEFORE you do it on your live system.
But again, i am not responsible for any other damage which could be caused. Good luck.
Cheers,