Found a fairly nasty bug with the Quest Editor Tool, though it should be really easy to fix.
The Quest Editor Tool is automatically changing this:
Code:
$npc->CastSpell(6536, $userid);
to this:
Code:
$npc->castSpell(6536, $userid);
And, since this command is case sensitive, it causes the script to fail when the
c is lower case.
I will keep an eye out for any more similar issues.