libspf2 breaks Postfix under FreeBSD4

Tue Mar 29 15:57:32 PST 2005

When postfix 2.2 is compiled with libspf2 support these are the errors
I am getting:

postfix/pipe[12943]: fatal: invalid option: ?
postfix/master[12919]: warning: process /usr/local/libexec/postfix/pipe pid 12943 exit status 1
postfix/master[12919]: warning: /usr/local/libexec/postfix/pipe: bad command startup -- throttling

Without SPF everything seems to work OK. This only happens with FreeBSD4.
FreeBSD5 seems to work OK with SPF included. Any ideas?