I recently recently installed Virtual Machine Manager 2008 and I started managing two of my host systems running Hyper-V. One is running Server Core and the other is a full installation.
I did hit a problem that caused me some problems, in the self service portal I was getting an error "Microsoft Hyper-V ActiveX Control failed to install", and no matter what I did it did not seem to install properly.
I finally discovered what was causing my problems. I am running Vista x64 and my browser was the 32bit Internet Explorer, once I switched to the 64bit Internet Explorer everything was fine. I presume the VMM Self Service Portal knew I was on a 64bit Operating System and kept giving me the 64 bit versions and the 32bit browser could not cope with it.
Now I just have to figure out why my Hyper-V cluster won’t be managed by VMM which I was able to manage when I was using the VMM beta. The other thing I am going to have to try and make work is the VMM library working on all my hosts. At the moment I can use the library for the host system that is running the library but I cannot get it to work yet for remote systems. I think it may be something to do with constrained delegation, it was certainly hinted at when I was doing some searches and reading through the VMM forums.
Anyway as I solve the problems (assuming I do :-)) I will do a post in case it may be a help to others.
Anthony's Blog 
Very helpful. Thank you