I've the same problem of Tai C. posted in november, but I can find out an answer in the mailing list archive.

My last modprobe.conf lines are:

options hostap_cs ignore_cis_vcc=1
options orinoco_cs ignore_cis_vcc=1
-e
install pcmcia /sbin/modprobe --ignore-install pcmcia && modprobe pxa2xx-cs

-e alias mwlan0 cfio
alias mwlan0 cfio
install cfio /sbin/modprobe --ignore-install cfio && /sbin/modprobe mcf25

and my gumstix doesn't boot.
If I comment these lines out, I get:

ifup: option with empty value "-e"

Help please!
Thanks
Claudio