Problem starting hostapd

[David Goodenough]

I am trying to set up a wireless access point using hostap.  I am running
this on a Debian Linux machine (using the supplied .deb files from sid)
and I am using kernel 2.4.20.  The wireless cards are Senao cards.

I have built the kernel modules, and I can use the wireless card in 
ad-hoc mode to talk to another machine which is running using the
ordinary orinoco(_cs) drivers.

So I want to move to managed mode.  So I use iwconfig to set the mode
and then I tried to start hostapd.  I am using a supplied hostapd.conf
file from the .deb file.  This specifies that I am using wlan0 which is
quite correct (at least I can iwconfig and ifconfig wlan0 successfully).

When I start hostapd, even with -dd as an option, it comes back with 
just two lines:-

ioctl(SIOCGIFINDEX): No such device
ioctl[SIOCGIFINDEX]: No such device

and that is it.

Nowwhere, even with -dd, does it tell me which device it is trying
to access, or what it is trying to do with it.

Anyone got any ideas.

I have yet to find a hostap howto, which may be part of my problem. 
Are there setup stages I need to have gone through first?

Regards

David