RemoteProcessRequest is a new action in the 1.2.1.2 rev of DTB and makes it possible for one PC to request another PC process a file. The idea behind this action is to off load the CPU time to another PC, so the MC can do other things (including nothing, keeping the HTPC cool).
It's important to keep in mind that the file paths are relative to the processing PC, not the requesting PC, so they will need to be adjusted (at the very least the path to the file being processed will need to be "UNC'd" for the processing PC to find it).
Personally, I use a profile that executes the WOL action to wakeup the remote PC, executes ChangContextValue using a regex to UNC the path (from d:\Recorded TV\file.dvr-ms to \\mymediacenter\recorded tv\file.dvr-ms), then executes RemoteProcessRequest to execute the desired profile remotely.