Setting up a WAP with WPA

[Jason Carson]

I am not sure where to ask this so I will ask here and hopefully someone
knows the answer. I am trying to set up a wireless access point with WPA
encryption.

I have my wireless setup with madwifi (v0.9.4) and wpa_supplicant 0.5.7 on
Gentoo Linux without any security.

I want to setup WPA and have been following this guide...
http://gentoo-wiki.com/Wireless/Access_point#WPA_Encryption

However I have ran into a problem with hostapd. When I start it up it says...

* Starting hostapd ...
Configuration file: /etc/hostapd/hostapd.conf
Using interface ath0 with hwaddr 00:19:5b:80:f2:d8 and ssid 'CarsonNet'
Flushing old station entries
ioctl[unknown???]: Invalid argument
Could not connect to kernel driver.
Deauthenticate all stations
rmdir[ctrl_interface]: No such file or directory
[ !! ]

It doesn't start and shows the following error message...

ioctl[unknown???]: Invalid argument
Could not connect to kernel driver.

...Does anybody know how to fix this?