Find this:

if($this->lock){
if(!$this->isAllowed($this->packet['m']['u'],6)) {$this->sendMessage("Sorry, Locking is on."); return;}
else{
echo "";
}
}
Replace it with this:

if($this->packet['m']['t']{0} == "!"){
if($this->lock){
if(!$this->isAllowed($this->packet['m']['u'],6)) {$this->sendMessage("Sorry, Locking is on."); return;}
else{
echo ""; //do nothing.
}
}
}