I've installed 2010 r2 client on Mac OS X Server v. 10.6.4. That was a trick in itself as I had to boot to 32 bit mode to install it, then back to 64 after installation.
Now that the system is installed and running, when my backup admin goes to the console to add the machine to the backups, he initially sees the machine but then can't access it. I stopped the process and then tried to run beremote manually with logging to the console. Here's what I get: