hey mike, yeah, I was fine until I went to 64 bit, too.  It sounds like we hit a similar problem. 
 
When I went to 64 bit I had no idea how much that would matter.  I'm finally starting to catch on, but after being away for a few years it's been a little challenging, to say the least.  I'm glad for the forums I go to.  I really do learn a lot from reading what others are doing. 
 
It makes sort of wonder though, whether the drivers for the midiman stuff needs to be "bridged" somehow to work with 64 bit, but I'm not computer savy enough to do anything about it.  I did use the drivers for a 64 bit windows 7 system though and they don't work on my system.  The issue seemed to stem from Windows too, not Sonar,,,, because I would get this when using a stand alone synth,,,  Somehow Mark of the Unicorn and Tapco found the secret sauce that M Audio didn't for their interfaces. 
 
 oh well, I'm happy with the Fastlane anyway.