Thought I would create a little "Reporting Services" checklist for DPM, not much but covers some common issues.
Must be installed on the remote SQL machine where the DPM databases are.
If the DPM database is not on the same server that DPM is installed on (referred to as the “remote” server), you MUST have run sqlprep.msi from the install folder of DPM on DPM server BEFORE installing DPM.
Script, Read and Write access must be enabled for the DPM Reporting Server virtual directories (httpHandlers in IIS 7.0).
Doug "bobTheBuilder" McCusker