AFAIK you're using the wrong module and wrong firmware. The 18.104.22.168 firmware should only be used with 3886 chip which you may not have. Unload the current module:
# modprobe p54pci
# modprobe p54common
Remove or rename the firmware file and place the 22.214.171.124 firmware at the same place, name it 'isl3890'.
Then load the proper module:
Then try master mode, set essid and bring up the interface:
# iwconfig ethx mode master essid "whatever"
# ifconfig ethx up
Should work - at least it does so here