This may work. can give it a try.
Code:
sub EVENT_ITEM
{
if(($itemcount{5018} == 1) &&
($itemcount{5019} == 1) &&
($itemcount{5020} == 1) &&
($itemcount{1179} == 1))
{quest::summonitem(5021); }
elsif(($itemcount{5019} == 1) &&
($itemcount{5020} == 1))
{quest::summonitem(5030); }
elsif(($itemcount{5019} == 1))
{quest::summonitem(5022); }
}