FuzzyOCR (and gocr) can't detect HGH spams

[Peter H. Lemieux]

I get a lot of messages with a gif ad for HGH drugs with this image: 
http://www.crystalmail.net/hgh.gif.  FuzzyOCR doesn't return anything 
because gocr doesn't show any text.  I've tried various -i settings for 
gocr from 1 to 254 and get gibberish at all settings.

For instance, 'gocr -i 180 hgh.gif' yields:
    lI__c_tc)r _rc_hc_rihc_Ll _cnLl .h1c_Llic_;cll_ _u__c_c __ihc LI
         l c htc)hlc_rc)c_c_ B llr_ll l hc r_cp_


    _ t4____ __cc_'un ic) __'ri_c _ hH3s, t_k   _ ,r o_E,y _h K E,_
    _ ,_ics r _ sncu)._r. t.ihk). lhirkrr x_))  '   gg __, r
    _ Krvc)_H t)r r_irk cct .__             _
                         O _' Y O ___ TE_ E
     _Lncl nLnn __ mc)R hnrtb

Results at other -i settings are about the same.

System is CentOS 4.3
gocr is at version 0.37 (from rpmforge)
netpbm is version 10.25

Any hints?

Peter