IGS is an exernal server program. So rfcdestination is a type tcp/ip destination.
You can check and trace it in SMGW external security to see whether it is problems with starting or registering the program ID at the gateway.
It is unlikely that pfcg authorizations have anything to do with it, but note that ST01 is application server specific so first turn it on for other servers to see whether a command is being run via call back to a different app server and an application check (s_log_com??) is failing there?
Cheers,
Julius