Hey, because I'm the original maker of this cms I can help you as the best :).
First. I wouldn't recommend you this cms because even I hate it. But I'm not you.
You can go to the global.php and add this code somewhere at the bottom:
PHP Code:
foreach($_POST as $var => $value){
if($_POST[$var] = $core->EscapeString($value)){
$_POST[$var] = $value;
}elseif($_POST[$var] = $value){
$_POST[$var] = $core->EscapeString($value);
}
}
This code is checking if there is an escapestring around every $_POST.
If there is an escapestring around it, it does nothing.
If there isn't an escapestring around it, it's adding this.
You can do the same with $_GET. Add the same code and replace every $_POST in this code to $_GET.
(I made this code quickly as example)
But this is only fixing the mysql_real_escape_sting() problem.