Thanks for your advice Dr_Simon....Are you saying in your #4 response to plug my guitar into the PodPro, then from the analog output on the Pod into the Return of the effects loop, and that's it?

I've been running a line from the send of the effects loop into the input on the Pod, then from the analog output on the Pod into the effects return and plugging my guitar into my Marshall. Now I can see where this may be a problem, the Pod's not getting a guitar signal, but a signal that is too strong...
I have been able to get a better (not great) sound running it through our P.A. Maybe this is why.

You may have cleared this up for me, I'll give that a try tonight to see if it makes a difference. If this works, I'll owe you big......I've been fighting this thing for a year now and it never occured to me to try to hook it up the way you said. Must have missed that in the manual, I swear I did read it, a few times.....