Ignoring the non-technical chatter for a moment...
Looking back over this thread, despite all the chatter about libspf and
libspf2, one thing from spf-help that doesn't appear to have been mentioned
on spf-discuss is that the SPF implementation being used by the original
poster is, "Michael Brumm's SPF filter on W2003 SMTP server". The original
poster on spf-help doesn't appear to have gotten a clear answer to his
question (other than your SPF record is fine, it's a bug).
http://archives.listbox.com/spf-help(_at_)v2(_dot_)listbox(_dot_)com/200407/0275.html
Just posting in the interests in getting back on the (still unresolved,
AFAICT) topic....
Scott Kitterman