This problem still exists for me, I still have to downgrade to run kernel
linux-image-2.6.32-5-xen-amd64_2.6.32-18_amd64.deb (from july 2010)
for it to work.
The discussion not leading to a solution can be found here:
In other words, most recent kernel in Debian stable does not work as a Dom0 kernel for me!
I have to go "in production" by the end of next week and it would feel much better to use a more recent Dom0 kernel