[Koha] Dealing with error 500

[Arnold]

hi 

i am new to koha and have gone through the "Using Koha as a Content
Management System" steps so as to be able to add custom pages. My problem is
when I finished adding a custom page and try testing it i get the error 500.

On checking the logs, it says;

[error][client 127.0.0.1] Can't open perl script
"usr/share/koha/opac/cgi-bin/opac/pages.pl": Permission denied, referer:
http://127.0.1.1/cgi-bin/koha/pages.pl?p=test

Any advice on how I can solve this?

Thanks