MsgRPC - Function Error

Hello all

I am using the function

MsgRPC(hMsg, "AlarmFirstTagRec", sAlarmTag+",^"^",^"^",^"MDG^"", 0)  ( MDG is the cluster)

but it is returning a cluster Error (Eror 417: Desc: 'Cluster required for operation').

The function AlarmFirstTagRec is expecting 4 arguments. In this case i want AlarmFirstTagRec(Tag,"","",Cluster), but it is not working.

Any ideas to solve this?

Thanks