[Exim] Permission denied when testing a new configure file?

Is the error message below the result of a security feature? If so, how
do you suggest working around it? Some features of Exim are impossible
to test without sending a message "for real". In my case I was testing
the system_filter_reply_transport and system_filter_user settings.
Running "exim -bF" does not report an error if the filter runs a "mail"
command and system_filter_reply_transport is unset.

[jpdalbec@mail03 jpdalbec]$ exim -C tgz/configure.exim jpdalbec@???

2003-01-29 09:51:15 Failed to create spool file
/usr/local/exim/spool/input//18dtYZ-0003MP-00-D: Permission denied
[jpdalbec@mail03 jpdalbec]$
Thanks,
John Dalbec