Just upgraded from WUP Pro 2006 where there was issues with this problem.  Tech support has told me 2 times that upgrading to WUP Gold v11 would fix this issue.  It hasn't.  Here is my error:

 "Failed to Connect to x.x.x.x.  User DOMAIN\AdminAccount Error = RPC server is unavailable.  " 

This is the same issue that was in WUP Pro 2006 - The old forum was located here:

http://www.ipswitch.com/forums/shwmessage.aspx?ForumID=14&MessageID=13737

Title = Windows "Server" service check reports false down

Old Error was:

 "Failed to create monitor interfaces. Did not actually check the service. HRESULT 800706ba  " with a post to the Sys Log saying DCOM error:

The reg hacks where tried - ThreadPoolCount, RPCTimeOut, TCPTimedWaitDelay, etc. Support was called 4 times with suggestions like - too many Windows Services being monitored at once, spread them all out by 5 seconds - this didn't work.  Not even on the servers with only 2 or 3 Windows Services. 

 - It'd be nice if Ipswitch could come up with a fix for this.  For now, I just tunned my monitoring back to only alert us if the services go down for more than 2 minutes.  Crappy work around if you ask me.  (users start calling if services are down for 45 seconds)

R

WUAmateur