error to connect usin .net connector

Hi, I,m having the fallow error when try to connect using sap .net connector.

SAP.Connector.RfcCommunicationException: Connect to message server failed

Connect_PM MSHOST=gtcdes13, R3NAME=000, GROUP=PUBLIC

LOCATION CPIC (TCP/IP) on local host gtcdes24

ERROR Group PUBLIC not found

TIME Thu Jan 24 10:50:28 2008

RELEASE 710

COMPONENT LG

VERSION 5

RC -6

MODULE lgxx.c

LINE 4353

DETAIL LgIGroupX

COUNTER 1

at SAP.Connector.SAPConnection.ThrowRfcException(RFC_ERROR_INFO_EX rfcerrInfo

, Encoding encoding)

at SAP.Connector.SAPConnection.Open()

at SAPReader.Proxy.connectSAP()

Someone have an idea for solve that?

Regards,