problem with ethernet connection when upgrading knx3.3 to 4

Hello,
Can anybody help me on that one ?
I am using an IBM portable 600E with a PCMCIA enet/modem combo card.
Using knx 3.3 works very well
When I try 3.4 or 3.6, the ethernet connection does not work
even if the card is recognized ( appears up in ifconfig )
Means first DHCP does not work
When I set a static address, I can send packets ( pings ) but the
packets are dropped when they are coming back ( means in ifconfig
that I can see TX incremented but RX stays null and dropped are incremented )
Thanks

Have you tried the network configuration script in the Start->Knoppix menu?