DPM 2007 jobs fail intermittently due to Agent RPC errors issue
One of the most difficult errors to troubleshoot is Error of DPM 2007: (ID 308 Details: The RPC server is unavailable (0x800706BA)), This error is caused by a networking infrastructure problem, It proved to be a problem querying the domain controller for DNS information using the Windows API call DsRoleGetPrimaryDomainName. The DPM agents call this many times during a job's life. If the call fails, DPM fails the job and generates error ID 308 Details: The RPC server is unavailable (0x800706BA).
please follow MS KB : KB970867
http://www.microsoft.com/downloads/details.aspx?FamilyID=aee949aa-d3e7-4b0f-b718-00b7c20f1257&displayLang=en
Islam Gomaa
Systems Administrator