I'm having a problem booting my Sharp Mobilon HC-4100

I loaded the following onto my CF card (I'm using a PCMCIA adapter):
pbsdboot1.exe
NetBSD.TX3912 (uncompressed kernel)
base.tgz (compressed)
kern.tgz (compressed)
etc.tgz (compressed)

The CF card is using a standard MSDos? filesystem.
The boot goes fine until it's time to mountroot.  This is what I get:

no file system for wd0 (dev 0x100)
cannot mount root, error = 79

Can someone explain what's going on here?  I'm assuming that I need to get a
BSD filesystem on my CF card, but how?
Can someone send me the exact procedure for partitioning the CF card,
formatting the new partitions and copying the files onto it?
I'm using OpenBSD on a laptop, but I assume any *BSD would have a similar
procedure.

Someone please help!

Thanks,
Brad T.