I got this message until I disabled hotplugging (I'm using ndiswrapper, not madwifi, but this looks like the same problem). You can disable hotplugging by adding the line
MII_NOT_SUPPORTED=yes
to the file
/etc/sysconfig/network-scripts/ifcfg-ath0
Alternatively, see here for how I fixed up drakconnect to recognise a new wireless driver, which allows you to set up everything using the GUI (no need to use iwconfig). The tick box for enabling/disabling hot-plugging is hidded under advanced options.