The blog post below is based on frequently asked questions on iis.net forums. Its an attempt to help diagnose and troubleshoot failures with remote management. It applies to all remote management (i.e. downlevel [XP, W2k3]--> 2K8 and 2k8-->2k8).
http://blogs.iis.net/nitashav/archive/2007/12/18/diagnose-failures-with-remote-management.aspx
Hope this helps
-Nitasha