This is waht I do to get mod_perl working under Apache 1.3.* on Slackware 11.0:
1. You need these modules from CPAN:
MIME::Base64
URI
HTML::Tagset
HTML::Parser
Digest-MD5
2. Download the source from
http://perl.apache.org/download/index.html and extract it as root;
3. Go to the new folder and type:
# perl Makefile.PL USE_APXS=1 WITH_APXS=/usr/bin/apxs EVERYTHING=1
# cp apaci/libperl.so /usr/libexec/apache/libperl.so
# chmod 755 /usr/libexec/apache/libperl.so
4. Verify if /etc/apache/http.conf has this line:
AddModule mod_perl.c
5. Stop & start Apache
# apachectl stop
# apachect start