OCS error Invalid command 'PerlSetEnv'

Hello,
I have just finished installing OCS Inventory Agent for Linux Server on Redhat Enterprise 4 but now my httpd service wont start, it is giving me the error below:

Starting httpd: Syntax error on line 16 of /etc/httpd/conf.d/ocsinventory.conf:
Invalid command 'PerlSetEnv', perhaps mis-spelled or defined by a module not included in the server configuration.

If anyone can assist will be most gratefull.

thanks in advance

Stavo.

Configuration: Red Hat Linux Firefox 1.5.0.3