I didn't upgrade the kernel and i have hotplug 0.0.20040329-22 and udev 0.056-3. I think the firmware version is correct, i deleted the firmware and got the same message in syslog (ipw-2.4-boot.fw load failed: Reason -2).
According to the driver source code, "Reason -2" is ENOENT : No such file or directory. IMHO, you did not put the firmware in the right directory. This is strange according to the information you provide. My firmware is in /usr/lib/hotplug/firmware if this helps but I use Sid with linux-2.6.17 Alexandre