PROBLEM SOLVED
After doing some reading I checked to see what firmware version my PMD-671 has. It was the original version that limited the CF size to 1GB.
I called Marantz and they emailed me a zip file with the firmware updates. After updating the firmware, my 4GB CF card is working just fine.
Also, my apologies for this new thread of an older topic. When I did a search I didnt see the previous thread.