Connection Failure to SAP


We used to get an occassional error and now its been bothering us more often. Please let me know if any of u have come across this error :

2002-10-18 09:16:17 EDT [B2B-SAP.0001.0007] ALE: OutboundProcess No Transaction for tid null

We get the above error when we try to post IDOCs to SAP. For posting the IDOCs to SAP, we created the routing rule which implicitly makes a ALE service call Outbound Process. When I throw in a IDOC file in the inbound directory via FTP, normally it is picked up by our service and makes a call to the routing service which in turn pushes into the SAP system. But sometime it does not and we see the above error.

We are not able to identify the real problem as we dont have this error in all of our systems like DEV, Sandbox and QA.

Any insight into this error will be really appreciated.

Thanks in advance.