SLD connection does not work

Hi experts,

Our PI system is connected to Solman SLD. This connection was working perfectly, but now SLDCHECK does not work. We have tested the RFC destinations LCRSAPRFC and SAPSLDAPI, and we get the following error:

Logon Connection Error

Error Details Error when opening an RFC connection (CPIC-CALL: 'ThSAPOCMINIT' : cmRc=19 thRc=7

Error Details ERROR: Error (Msg DGW                  748 not found)

Error Details LOCATION: SAP-Server XXXX_00 on host XXXX (wp 3)

Error Details COMPONENT: CPIC

Error Details COUNTER: 7

Error Details MODULE:

Error Details LINE:

Error Details RETURN CODE: 748

Error Details SUBRC: 0

Error Details RELEASE: 721

Error Details TIME: Mon Sep  2 17:07:12 2013

Error Details VERSION:

SLD and JCO RFC Providers service are running, as well as the Programs ID configured. All were stopped and restarted again, included the JCO RFC service. All data are correct (Program ID name, Gateway, and so on), but RFC testing does not work.

Any idea to check?

Thanks in advance,

Samantha.