FuzzyOcr misses

I've gotten a number of image spams that don't trigger FuzzyOcr at all for some reason, e.g. http://www.os2.dhs.org/~john/DPO.gif

If I run the email through spamassassin manually, e.g. "spamassassin -D FuzzyOcr < DPO.eml" there's no indication that FuzzyOcr found anything at all:

[66152] dbg: FuzzyOcr: Score{autodisable} = 1000
[66152] dbg: FuzzyOcr: Using gifsicle => /usr/local/bin/gifsicle
[66152] dbg: FuzzyOcr: Using giffix => /usr/local/bin/giffix
[66152] dbg: FuzzyOcr: Using giftext => /usr/local/bin/giftext
[66152] dbg: FuzzyOcr: Using gifinter => /usr/local/bin/gifinter
[66152] dbg: FuzzyOcr: Using giftopnm => /usr/local/bin/giftopnm
[66152] dbg: FuzzyOcr: Using jpegtopnm => /usr/local/bin/jpegtopnm
[66152] dbg: FuzzyOcr: Using pngtopnm => /usr/local/bin/pngtopnm
[66152] dbg: FuzzyOcr: Using bmptopnm => /usr/local/bin/bmptopnm
[66152] dbg: FuzzyOcr: Using tifftopnm => /usr/local/bin/tifftopnm
[66152] dbg: FuzzyOcr: Using ppmhist => /usr/local/bin/ppmhist
[66152] dbg: FuzzyOcr: Using pamfile => /usr/local/bin/pamfile
[66152] dbg: FuzzyOcr: Using gocr => /usr/local/bin/gocr
[66152] dbg: FuzzyOcr: Using ocrad => /usr/local/bin/ocrad
[66152] dbg: FuzzyOcr: Loaded <62> words from
"/usr/local/etc/mail/spamassassin/FuzzyOcr.words"
[66152] dbg: FuzzyOcr: Using scan: $gocr -i $pfile
[66152] dbg: FuzzyOcr: Using scan: $gocr -l 180 -d 2 -i $pfile
[66152] info: rules: meta test FM_DDDD_TIMES_2 has dependency
'FH_HOST_EQ_D_D_D_D' with a zero score
[66152] info: rules: meta test FM_SEX_HOSTDDDD has dependency
'FH_HOST_EQ_D_D_D_D' with a zero score
[66152] dbg: FuzzyOcr: Saved: /tmp/.spamassassin661528qp1mltmp/raw.eml
[66152] dbg: FuzzyOcr: Wrote:

/tmp/.spamassassin661528qp1mltmp/8oNs11_f1_.gif
[66152] dbg: FuzzyOcr: Found: 1 images
[66152] dbg: FuzzyOcr: Errors to: /tmp/.spamassassin661528qp1mltmp/raw.err
[66152] dbg: FuzzyOcr: Analyzing file with content-type="image/gif"
[66152] dbg: FuzzyOcr: pfile =>

/tmp/.spamassassin661528qp1mltmp/8oNs11_f1_.gif.pnm
[66152] dbg: FuzzyOcr: efile =>

/tmp/.spamassassin661528qp1mltmp/8oNs11_f1_.gif.err
[66152] dbg: FuzzyOcr: Found GIF header name="8oNs11_f1_.gif"
[66152] dbg: FuzzyOcr: Image is single non-interlaced...
[66152] dbg: FuzzyOcr: Image hashing disabled in configuration, skipping...
[66152] dbg: FuzzyOcr: Trying: $gocr -i $pfile
[66152] dbg: FuzzyOcr: Trying: $gocr -l 180 -d 2 -i $pfile
[66152] dbg: FuzzyOcr: Remove DIR: /tmp/.spamassassin661528qp1mltmp
[66152] dbg: FuzzyOcr: FuzzyOcr ending successfully...

Using spamassassin-3.2.3, FuzzyOcr-3.4, gocr-0.44, ocrad-0.16 on FreeBSD-6.2. If I use the FuzzyOcr sample image spams, it seems to work. What gives?

-- 
John Thompson (john@os2.dhs.org)
Appleton WI USA