What does the DR section under the "System" tab show? Are the machines listed there, and when you render with DR, what does the DR tab show in the VFB? Does it show that it is seeing the render nodes?
I've noticed that lately, probably due to some changes in Windows I'm guessing, that I can't auto-discover my machines any more and have to manually enter the IP addresses. This may be related to the removal of the Windows Home Group or some such thing, though I haven't had time to dive in and test.
