ip-up.d / can't start script

["ktb" <xyf@inetnebr.com>]

I've searched the archives and I can't find my answer.  I used pppconfig to
create my dialup.  I need to start my firewall *after* I have logged onto
the Internet.  I looked in "ip-up" and it looks to me like it uses scripts
placed in "/etc/ppp/ip-up.d".  I place a simple Perl script (that works from
the command line) in "/etc/ppp/ip-up.d".  Logged out and back in and tried
"pon"  I logged on fine by my script didn't run to start my firewall.  I set
permission and ownership exactly the same as "exim" in the said directory.
I'm using Slink.  What am I doing wrong here?
Thanks,
kent