I seem to have resolved the issue!
Here is what I'm running:
Windows 7 Home Premium 64-bit version
ASCOM 5.5 Platform with updates installed
Maxim DL Pro 5.08
Latest 64-bit ASCOM driver for the QHY8Pro
The 64-bit QHY8Pro driver installed correcly with no errors.
After installing everything and then opening MaximDL Pro 5.08 "QHY8Pro" appears on the list of cameras available for connection: (See attachment: QHY8Pro-Select.jpg).
If you select the QHY8Pro camera and then try to connect you get the error as shown in the attachment (QHY8ProError1.jpg)
Do this instead:
From the drop down for camera selection, choose the ASCOM option. (see attachment:ASCOM-Select1.jpg).
After selecting ASCOM from the list of cameras, click on the "Advanced" button. You will then get an ASCOM popup dialog that will allow you to choose the QHY8Pro camera. (See attachment: ASCOM-Select1.jpg).
I was able to get the camera to connect and operational after making the above selection.
Hope this helps others with similar setups who are experiencing connection problems.