Actually I read about enabling the "optional" RHEL repo while researching this problem so I had done that as well.
Manually installing things made it so the system only had to get that last dependency and then it went ahead and installed BackupPC.
Reading the docs, it's the final frontier...
Now the real fun starts, getting BackupPC configured and working.
Sometimes I wonder how I get myself into these things.
Just an FYI, you probably avoided this problem (the hard way) by
manually installing some of the perl packages. They are available in
an optional RHEL (not EPEL) repository that is disabled by default.
See the following bug for details: