In that case, you'll want to make sure that the account that is used by the webserver to run the script has the proper permissions. To have your script tell you what account that is, insert into your script:

printf "user/group:%s/%s</br>\n",scalar getpwuid( $< ), scalar getgrgi
+d( $( );
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This user needs to have access to the directories your system uses to store it's perl-modules.