I've posted this in the main RD thread without any response, so I wanted to try it as a new thread and see if I got any better responses.

I have a PowerPak and both a top loading NES and a silver/black RetroDuo. The CF cards appear to be generic (SimpleTech). The PowerPak works perfectly in the NES, but continually says 'card reading error' on the RetroDuo.

As the RD works perfectly, my belief is that there are compatibility issues with the RD and some types of CF cards. For anyone who's using a PowerPak on a RetroDuo, I'd appreciate it if you would post what brand(s) of CF cards you're using.