When you have more than one driver assigned in the PLC Name and Port table, you need to include the PLC name in the addressing for any PLC reference. The addressing is expressed inside square brackets whenever to apply a PLC address and that's where you would have to include the PLC name.
If your company will permit it, post your configuration file here. I'll take a look at it and see if I can help steer you in the right direction. I don't have a PanelMate to try to download to, but I have the software.
I your employer objects to your posting the file to a public forum, send me a private message through the forum. I'll send you my email address and perhaps they'll permit sending the file to me privately.