addUseItemcallback is not within a function ,too
try this
void OnStart (){
SetEntityCallbackFunc("GuestRoomKey", "jump");
AddUseItemCallback("", "GuestRoomKey", "door01", "UsedKeyOnDoor", true);
}
void UsedKeyOnDoor(string &in asItem, string &in asEntity)
{
SetSwingDoorLocked("door01", false, true);
PlaySoundAtEntity("", "Unlock_door", "door01", 0, false);
RemoveItem("GuestRoomKey");
}
void jump(string &in asEntity, string &in type)
{
SetEntityActive("corpse01", true);
PlaySoundAtEntity("", "21_screams.snt", "corpse01", 0, false);
}
void OnEnter()
{
}
void OnLeave()
{
}
you should invest more time in your programming in general.
you could start by reading this guide
http://wiki.frictionalgames.com/hpl2/amn..._and_guide