The problem is caused by a registry key access violation.
I get the same error message but it does not seem to affect anything, although I am not currently using the Http adapter on BTS2006.
The recommended fix is to use run Registry Monitor (download from [url]http://www.sysinternals.com[/url]) to identify the registry keys that are causing the problem and change the security permissions. Probably giving the user that the Biztalk Isolated host is using read/write access