A few things to try:

1) Make sure that it is formatted to FAT or FAT16 and not FAT32.

2) Push the card in and out a few times in case you have dirty socket contacts – this system is probably 10 years old and corrosion is possible.

3) Try and find a smaller card – when this software was written, 64M was a BIG card.

4) Consider leaving it as it is.

5) If all else fails, you'll probably have to send it in to be looked at.