vb 2.2.9 BUG!!! it doesn't delete sub-forums

hi everybody...
i'm making an hack for my vb 2.2.9 forum.
this allow to add, edit and remove forums to some restricted users in a non-vb page.

to delete forums and sub-forums i've used the vb function:

// ************************************** //
$forums=$DB_site->query("SELECT forumid FROM forum WHERE INSTR(CONCAT(',',parentlist,','), ',$forumid,')>0");
$forumlist = "0";
while($thisforum=$DB_site->fetch_array($forums)) {
$forumlist .= ",$thisforum[forumid]";
}

$DB_site->query("DELETE FROM forum WHERE forumid IN ($forumlist)");
// ************************************** //

but this doesn't delete my sub-forums.

so i tryed to do it forum AdminCP and... BUG!!! this doesn't delete sub-forums too.

they are not visibile in forums list, but in my sql database they are still there...


why??? what's the problem???

thanks in advance and sorry 4 my bad english

by3z 4ll