[BenChen]

Actually, it turned out to be slightly more than that. I had to remove a 'try... catch' in the PRS+ activation script (FreeCell.js). Then it worked fine in my PRS+ 2.0.x custom build:

I changed

		   try {
			kbook.autoRunRoot.sandbox.getSoValue = Core.system.getSoValue;
			kbook.autoRunRoot.sandbox.hasNumericButtons = Core.config.compat.hasNumericButtons;
			} catch (ignore) {}

to

			kbook.autoRunRoot.sandbox.getSoValue = Core.system.getSoValue;
			kbook.autoRunRoot.sandbox.hasNumericButtons = Core.config.compat.hasNumericButtons;

Not sure what is going on, but it is now working on my PRS-600.

Thanks,
Ben.

P.S. I've updated the attachment in post #104