Hmm, the setting up process itself seems OK.

In my Knoppix 5.1.1 system, I have never seen a "Interrupt:3 Base address:0xd400" type report; don't know whether this signifies a card set-up issue specific to your CNet Pro200W .

FWIW this is the report I get for my Knoppix 5.1.1 HD-installation
Code:
eth0      Link encap:Ethernet  HWaddr 00:50:8B:65:3A:6C  
          inet addr:192.168.2.92  Bcast:192.168.2.255  Mask:255.255.255.0
          inet6 addr: fe80::250:8bff:fe65:3a6c/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:215 errors:0 dropped:0 overruns:0 frame:0
          TX packets:295 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:20142 (19.6 KiB)  TX bytes:30516 (29.8 KiB)

lo        Link encap:Local Loopback  
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:85 errors:0 dropped:0 overruns:0 frame:0
          TX packets:85 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:6188 (6.0 KiB)  TX bytes:6188 (6.0 KiB)
BTW I notice that you don't have an "inet6 addr: ..." line reported for eth0.

Other questions that occur - presumably your PC/Router works OK with (which) other operating system(s) ... you're not using a firewall ... ?
[EDITED to qualify differences between Knoppix 5.1.1 and 3.7 ]
I dug out & rebooted my KNOPPIX 3.7 , which, unlike 5.1.1, has *never* given me configuration problems
and for ifconfig it gives
Code:
eth0      Link encap:Ethernet  HWaddr 00:50:8B:65:3A:6C
          inet addr:192.168.2.92  Bcast:255.255.255.255  Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:307 errors:0 dropped:0 overruns:0 frame:0
          TX packets:330 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:298698 (291.6 KiB)  TX bytes:56169 (54.8 KiB)
          Interrupt:10 Base address:0xe000 Memory:e1102000-e1102038

lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:10 errors:0 dropped:0 overruns:0 frame:0
          TX packets:10 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:500 (500.0 b)  TX bytes:500 (500.0 b)
i notice that:
The Interrupt is reported, but with Memory extent included (which is not in your ifconfig - this may be significant).
Knoppix 3.7 does not use inet6 - just BTW.