pcmcia network card

[Gerald]

Hi

I'm using Knoppix installed on HD with an Thinkpad 600X.

For Network Connnections I am using a pcmcia card.
The card is a XIRCOM CreditCard Ethernet 10/100 CE3B-100

Everytime I transfer 6 MBytes or more through the
Ethernet the whole System stops.
I think it is something with the network-card

Internal it is working ok (cron, syslogd and so on) but
ist doesn't accept any connection from the user.
No network (ifconfig still shows UP),
no keyboard and no display.

Does anybody know where to look for the problem?
There is absolut no entry in syslog

Thanks a lot
Gerald