My LANG variable was set to "en_US" in both the ...api/bin directory as well as 
for user:oracle.  

We were able to backup RMAN to disk successfully.  

As this is a new (replacement server) for one of our SP nodes, I copied the 
license file from this SP node onto the new server and then 
downloaded/installed TDP2210.  I have ordered the TDP 22 installation media and 
will try a clean install of that when I get it.

I'll keep you posted.

Thanks to everyone for the help thus far;
Theresa