Is the DFE650 problem solved now ???
I have a similar problem, kernel 2.2.16-3 (redhat), pcmcia card services 3.1.8, DFE 650 on Toshiba Satellite 2210XCDS.
The card is detected (two beeps), ping to eth0 IP works
but to default gateway doesn't.
On /var/log/messages appears:
eth0: found link beat
eth0: lost link beat (one second later)