Here's an example of the full error report that you might see:

Syntax error on line 393 of /home/httpd/httpd_perl/conf/httpd.conf:
Invalid command 'PerlHandler', perhaps mis-spelled or
defined by a module not included in the server
configuration [FAILED]

You might get this error when you have a mod_perl-enabled Apache server compiled with DSO, but the mod_perl module isn't loaded. (This generally happens when it's an installed RPM or other binary package.) In this case you have to tell Apache to load mod_perl by adding the following line to your httpd.conf file:

AddModule mod_perl.c

You might also get this error when you try to run a non-mod_perl Apache server using the httpd.conf file from a mod_perl server.