Well, I appreciate the reply. However, the advice you've given is a bit late, and I already learned it the hard way...
At this point, I'm not concerned with what version of MythTV needs to be used, but where I might find the pluto-dcerouter package. It is not available via apt-get, although it is referred to. I'm currently scouring the DVD-DL image, and will be searching thru the CD image as well, if I must.
Thought somebody might be able to offer a new repo URL, as I always get apt errors about package lists not found on the standard apt sources, that might assist my rescuing this system...