Sometimes you will have to change the permissions of a file. I had to do this recently to get an installation of WordPress blog to run. Here is how to change file permissions using cPanel:

•     log into cPanel
•     look for File Manager and follow the link
•     you will get a window that says Please select a directory to open: and a number of options
•     select Web Root (public_html/www)
•     look at the far right column. It says Perms These are the file permissions for each file using the standard Unix file permissions numbering system
•     click the permissions for the file you want to change you can edit it right on the web page
•     click “OK”

In a nutshell, cPanel is giving you an easy interface for doing a chmod.
Unix and Unix-type file permissions appear quite cryptic at first but are easy to understand. More info at Linux File Permission Confusion and other sites you can google.