Thanks to Kir's work on the mantis ticket, mine is now working. All I had to do for each MD, is to the following from a command prompt on my (Ubuntu) desktop computer:
1)ssh into the core
..enter password 'linuxmce'
2) navigate to /usr/pluto/diskless
3) get the "moon numbers" of the media directors
note that each media director has a unique 3-digit number.. you will need this number in the following steps..
4) change over to the root user:
...enter password 'linuxmce'
5) ssh into one of the media directors
(xxx is the 3-digit number of one of the media directors)
6) now go into the etc directory of the media director
7) Now we are going to replace the file that is causing the problems...
Backup the file
mv auto.PlutoStorageDevices auto.PlutoStorageDevices.original
9) Get the new updated file from SVN
10) Update the file permissions
chmod 755 auto.PlutoStorageDevices
Do this for each media director, and you will be back in business.. (there may be better/faster ways to do this, but this is what worked for me)
Of course, if you are not familiar with the command line, you can seriously mess things up, so do this at your own risk! You may be better off waiting for the full 0710 release if this is the case.
Thanks again Kir for the information to get this working!