[mADmAX`]

Nevermind, I am so stupid...

I tried this already but I forgot one thing...

// ############################### start do open/close posts ###############################
if ($action=="openclosepost") {

$post=$DB_site->query_first("SELECT * FROM post WHERE postid=$postid[postid]");

if ($bbuserinfo[usergroupid]==5 or $bbuserinfo[usergroupid]==6 or $bbuserinfo[usergroupid]==16) {
if ($post[openpost] == 1) {
$DB_site->query("UPDATE post SET openpost=0 WHERE postid='$post[postid]'");
eval("standardredirect(\"".gettemplate("redirect_t hreadclosed")."\",\"showthread .php?s=$session[sessionhash]&threadid=$threadid\");");
}
if ($post[openpost] == 0) {
$DB_site->query("UPDATE post SET openpost=1 WHERE postid='$post[postid]'");
eval("standardredirect(\"".gettemplate("redirect_t hreadopen")."\",\"showthread.p hp?s=$session[sessionhash]&threadid=$threadid\");");
}
}
}

I had this...
if ($HTTP_POST_VARS['action']=="openclosepost") {

instead of this...
if ($action=="openclosepost") {