When using the SAP Adapter, while receiving an IDoc, you might see the error message "Loading property information list by namespace failed or property not found in the list" in the event log.
Cause: The SAP adapter is promoting the IDoc control record fields in/to the BizTalk message context. However, there is no schema deployed for these context properties.
Resolution: Add the "Microsoft.Adapters.SAP.BizTalkPropertySchema" dll to the Resources section of your BizTalk application.
The post http://blogs.msdn.com/adapters/archive/2007/10/12/enablebiztalklayeredchannel-what-does-this-binding-property-do-part-1.aspx talks about this in a little more detail (of course - EnableBizTalkLayeredChannel was renamed to EnableBizTalkCompatibilityMode from the RC build onwards).