spoof:// format error / example page
well you didnt format the spoof url correctly
the format should be like
spoof://www.test.com;ref://www.spooftest.org
now a place to test the referrer would be as spoof url:
spoof://refspoof.mozdev.org/referrer.php;ref://www.spooftest.org/SpOOf
or with more properties
spoof://l4x.org/i.php;ref://www.spooftest.org/SpOOf
for a litte fun