Thinkpad 600 with Xircom Creditcard freezes

[Gerald]

Hi there

I used hdinstall to install Knoppix on my IBM Thinkpad 600X.
This Laptop has a Xircom Creditcard 10/100 Modell CE3B-100
as pcmcia Networking adapter.

The system ist super and runs for days, but
when I use the network to transfer some files, it just freezes.

When I try to transfer about 6-8 Mbytes to the System,
it just doesn't accept any input any more.

I think the kernel is just working fine, because all processes
like cron and syslog are still working. But
I can't access the system.
No network, no keyboard and no display.
An "ifconfig" started via cronjob every 5 min
shows the Interface eth0 is UP.
And no error in /var/log/messages.

Is there anybody who can help ?
Or perhaps knows where to look?

thanks a lot
Gerald