Failed to register adapter <...> for receive location
Everyone gets this error in the event log every once in a while -
The Messaging Engine failed to register the adapter for "<...>" for the receive location "<...>".
Please verify that the receive location exists, and that the isolated adapter runs under an account that has access to the BizTalk databases.
Mostly I get this when I publish a new BizTalk web service and forget to selected the correct application pool (using windows service 2003).
Often this comes up when setting up an XP (or Vista) workstations for the first time and forgetting to sort out ASPNET permissions.
Sometimes it is simply a typo in the receive location's url, or a problem the script that was supposed to enable it, all of those are pretty much suggested through the event log entry message.
But earlier this week I had another case, one which never happened to me before (and, arguably, shouldn't have happened at all, but if it did for me, there must be another idiot who would do the same! :-)), and that one is not mentioned in the message -
I have published an orchestration web service, selected the correct application pool and made sure the receive location was enabled but still this error would be logged.
What I didn't do (I blame it on having a cold) is to actually create an instance of the host under which the receive location is configured to run; I had a host configured and selected but no host instance...