How to deal with wpa_supplicant error?

I'm using Ubuntu 11.10 and I've copied the wpa_supplicant configs from another computer running Ubuntu 11.10, which is connected to my home network.

The non-connecting device has an Intel wireless card which uses the ipw2100 driver and the wireless interface is called eth1. Issuing the iwlist scanning command shows that the card can see my network SSID (along with several others).

However, when I run the command:

wpa_supplicant -Dwext -ieth1 -c/etc/wpa_supplicant.conf

I get the error message:

wpa_supplicant ioctl[SIOCSIWENCODEEXT]: Invalid argument 

Any guidance on explaining this error and help in getting wpa_supplicant to work giving me connectivity to my home network would be greatly appreciated.

Solution 1:

SOLVED: The wired interface (eth0 in my case) must be shut down otherwise it appears to disrupt the correct operation of the wireless interface (eth1 in my case) and wpa_supplicant.