Advise on getting the usb firmware to work on classe cp-800

Hmmm.... Is the CP-800 new to you, or have you been using it a long time?
A drawback of the CP-800 (as you probably know) is the lack of sub level controls. You have to set the sub level(s) manually at the subs to match the mains.

On the CP-800 itself, I’d make sure that the Configuration was correct for the subs and output connectors you’re using and that the selected input is using that configuration.

Also, check the manual to make sure you’re using the right output connector for the sub. I believe that for a single sub, it’s the one all the way on the right, if you are facing the back of the unit.

Does any of that help?

Yes, you are right on the sub output location. I have gone over everything several times for sure. I have had it since October of last year. Currently it is not hooked up, as I removed it from my stack to factory reset, etc. I will run through the paces one more time. Never know! 
I am going to contact Classe as well about an upgrade.

Thanks for your help I appreciate it.

You're welcome -- I wish you best of luck with it.