I made a mistake and used Webmin to update packages on my Debian Lenny install and I'm now no longer able to connect to my router via eth0 or ath0 (using madwifi).

I get an error message at boot which states that it is unable to read /etc/network/interfaces:5: Unknown address type

I attempted to m-a a-i madwifi and this asked for the linx-headers which I've now reinstalled using the downloaded .deb file and have managed to get madwifi installed and the ath0 is now available but I can't get it to connect to the router which is using WPA-PSK. I don't know the commands as I'm slowly learning linux as I've been a lifelong Windows user (loving it so far).

My interfaces config for ath0 is as follows:-

auto lo
iface lo loopback

auto ath0
iface ath0 inet static
address 192.168.x.xxx
netmask 255.255.255.0
network 192.168.x.xxx
broadcast 192.168.x.xxx
gateway 192.168.x.xxx

wpa-conf /etc/wpa_supplicant/wpa_supplicant.conf

How do I get Debian to read the interfaces file and / or how do I manually connect to my router?

Thanks in advance

The error looks like from parsing the file, not physically reading it. I can see no errors in the part of your interfaces file you posted. Look for the error in logs, maybe there are some more detailed informations.

Usually the easiest way to connect is by cable and eth0. Can you connect a cable between your computer and router?
Let us know what you got from ifconfig and iwconfig command.