GFE pcmcia card (8139too) - what magic?

I'm using Knoppix 3.6 (2.6.7 kernel) on my ancient NEC Ready 340T with a cheap GFE 10/100 FastEthernet lan card and all is well. However, using a self-compiled vanilla 2.6.9 kernel, the laptop hangs when I try to access the lan, and I need to eject the lan card to regain access to the system. At this point, if I re-insert the lan card, the system locks up again. What's the secret to getting this lan card to work properly with a new kernel?

TIA
Rockdoctor

Update: With the vanilla 2.6.9 kernel installed, if I ping the laptop from another machine on the lan, I get the first packet back, then the laptop locks up.