You may experience missing assemblies with the March CTP release of the HPC Server 2008 Pack SDK.   Specifically, within the SDK installation 'bin' folder path, the only included assembly is 'Microsoft.Hpc.Scheduler.dll'.   The 'Microsoft.Scheduler.Properties.dll' and the 'Microsoft.Hpc.Scheduler.Session.dll' assemblies are missing.   In order to get these onto your development machine, you'll also need to install the "HPC Pack".   The HPC Pack may be installed in one of 3 modes.  On a cluster client workstation, just install it using the "Client Utilities" mode.