[Exim] Problems installing SpamAssassin with exim

I figured I'd give SpamAssassin a fair shake, but am having trouble
getting it up and running.

I used perl's CPAN module for installation, then added to the following:

to ~greg/.forward:
"|IFS=' ' && exec /usr/bin/procmail -f- || exit 75 #greg"
(also tried it without the quotes. /usr/bin/procmail exists)

and to .procmailrc:
:0fw
| /usr/bin/spamassassin -P -c /home/greg/.spamassassin/rules
(both locations exist and have correct permissions...I copied the rules
directory from /root/.cpan/build/Mail-SpamAssassin-2.11/rules)

...with these in place, all mail I send to myself or is coming in from the
internet gets stuck in the incoming mail queue (visible from
/usr/exim/bin/exim -bp).

What am I doing wrong?

Greg