You can run without mod_perl but the speed will not be so good, since ISPMan will have to make a connection to the LDAP server and create the objects each time you load any page.
ISPMan also requires some way of authentication for users. It will not work properly unless a user is authentified and a $ENV{'REMOTE_USER'} is set. I use mod_ldap.1.8.c for authentification and I will explain in the rest of the document on how to set that up.
Create a build directory.
/opt/ispman/build
(I like the keep the sources and the build even on production machines so that I can make a change if I want to quickly rather than looking for sources and remembering what I did before to get this software compiled)
cd to that directory.
You may obtain the sources either from a mirror or from the links provided.
obtain sources of apache from http://httpd.apache.org/dist/apache_1.3.14.tar.gz
obtain sources of mod_perl from CPAN http://www.cpan.org/authors/id/DOUGM/mod_perl-1.24_01.tar.gz
obtain mod_ldap.c from http://www.kie.berkeley.edu/people/jmorrow/mod_ldap/mod_ldap.1.8.c.tar.gz
untar all files.
rename apache-1.3.xx to apache
rename mod_perl-1.24.xx to mod_perl
rename mod_ldap.1.8.c to mod_ldap.c
move mod_ldap.c to apache_1.3.14/src/modules/extra directory
copy the Makefile.ISPMan.apache to Makefile in /opt/ispman/build
cp Makefile.ISPMan.apache /opt/ispman/build/Makefile
EDIT the Makefile if neccessary
cd to /opt/ispman/build and run
make all
this should build apache with mod_perl and mod_ldap for you.
For more information see the Makefile