getting ipw2100 to find its firmware at boot time?

[Dick Davies <rasputnik@gmail.com>]

I just built the ipw2100 module under etch according to 
  http://blogs.cocoondev.org/michaelm/archives/002084.html
everything seemed to go fine, and when I tweak /etc/network/interfaces I can

# modprobe ipw2100
# ifup eth2

and dhcp etc works fine

(eth0 = built in ethernet, eth1 = ip-over-firewire)

I'm trying to figure out how to load the module automatically at boot time.

I added 'ipw2100' to /etc/modules and rebooted, and I get this error:

  hypnotoad:/home/rasputnik# dmesg|grep ipw
  ipw2100: no version for "ieee80211_get_crypto_ops" found: kernel tainted.
  ipw2100: Intel(R) PRO/Wireless 2100 Network Driver, 1.1.2
  ipw2100: Copyright(c) 2003-2005 Intel Corporation
  ipw2100: Detected Intel PRO/Wireless 2100 Network Connection
  ipw2100: eth0: Firmware 'ipw2100-1.3.fw' not available or load failed.
  ipw2100: eth0: ipw2100_get_firmware failed: -2
  ipw2100: eth0: Failed to power on the adapter.
  ipw2100: eth0: Failed to start the firmware.
  ipw2100Error calling register_netdev.
  ipw2100: probe of 0000:01:05.0 failed with error -5

(After i login a 'modprobe ipw2100; ifup eth2' outputs this to dmesg :
  ipw2100: Intel(R) PRO/Wireless 2100 Network Driver, 1.1.2
  ipw2100: Copyright(c) 2003-2005 Intel Corporation
  ipw2100: Detected Intel PRO/Wireless 2100 Network Connection
)

Couple of reasons this could happen spring to mind

1. eth0 isn't a wireless interface (though not sure why that works in
multi-user)
2. /usr isn't mounted when modprobe runs
3. I have something back-asswards ...

What's the 'Debian Way' to load ipw2100 modules? 
Thanks.