IS Crashing when receiving the IDOC

Hi All,

I am facing an issue in receiving the SAP IDOC.
I have one SAP adapter configured with application X,who are using the SAP version 7.0 and the webMethods version i am using is 6.1.Whenever an IDOC is received from application side…wM IS getting crasehd saying
“Connection Error
Error when opening an RFC connection
ERROR: program XXX not registered”

Its happening for particular IDOC’s only and i am not not even receiving the those IDOC’s for those the IS getting crashed.

Any of you faced this issue? Let me know what i can do for this if any of you can.Thanking in advance.