We recently had an issue where we had a lot of a receive locations connecting to the same server (sum 1,200).
They kept going down complaining the Messaging Engine failed while notifying an adapter of its configuration
and The error threshold was exceeded
The fix is explained in the following KB article:
http://support.microsoft.com/kb/810886/en-us
For the MaxCmds and MaxMpxCt values, it should be set at 10000 (decimal)
This setting needs to be on all of the BizTalk machines AND the file server it is connecting to.
After you make the change, you have to reboot the machines where this registry change happened.
How to test:
Open up perfmon and add a counter from Redirector called Current Commands
In which you will see the number of connections open (in this case 627)
Did I mention the disclaimer on the side of my blog?