Could have been that the certificate on the sub didnt match what was on the SFTP server.  We are using freeftpd.  I found that after I reinstalled freeftpd it backed up fine.  Thanks for your comments.

Did you get a resolution to this ? I am seeing exactly the same issue on our server, we are running CUCM 8.0.2

You cant install a CUCM 7 dial plan on CUCM 8, but you can upgrade from a dialplan on 6 or 7 to CUCM 8 and the dial plan will stil work.