Your NPC called 'Versus' is trying to delete some items an user doesn't have, then making that error appear.
I'd suggest changing the
delitem 7420,10;
On the source of that NPC for something like this:
// Rest of NPC hereif ( countitem(7420) > 10 ) { delitem 7420,10; }else if ( countitem(7420) > 0 ) { delitem 7420, countitem(7420); }// Rest of NPC here
This way, the error should be gone.