AddEntityCollideCallback bug, need help

[omiwrench8k]

Alright, so when I try running this code: void OnEnter ( )
{
AddEntityCollideCallback ("Player", "PlayerCollide",

"MonsterFunction", true, 1);
AddEntityCollideCallback ("monster_grunt_2", "MonsterCollide_1"
"MonsterTwoDissapear", true, 1);

}
void MonsterFunction (string &in asParent, string &in asChild, int

alState){
SetEntityActive ("severant_grunt_1", true);
ShowEnemyPlayerPosition ("monster_grunt");
}

void OnLeave ( ){

}

It gives me the error message: main(4,2) : ERR : No matching signatures to 'AddEntityCollideCallback(string@&, string@&, const bool, const uint)'

Anyone know what the problem is? Thanks!