how can i enable the sap listener?

hi all
when i enable the sap listener, it has an error as following:T:2624 ======> Connect from SAP gateway to RFC server failed
Connect_PM GWHOST=R3SERVER, GWSERV=sapgw00, TPNAME=ISIDS

LOCATION SAP-Gateway on host r3server / sapgw00
ERROR program ISIDS not registered

TIME Fri Sep 01 13:39:58 2006
RELEASE 620
COMPONENT SAP-Gateway
VERSION 2
RC 679
MODULE gwr3cpic.c
LINE 1594
DETAIL TP ISIDS not registered
COUNTER 8

how can i deal with it?

regards

fang