Unix keeps track of "File Permissions" for each file and directory. These permissions typically state what is allowed to Read, Write, and Execute them. This methodology allows Unix to control the ability of users and programs to access files, as well as to prevent files which were not intended to be program files from being executed. Permissions are specified by a three digit number, such as 755 or 777.
Our software needs its scripts to have their execute permissions turned on, and it needs to be able to Read and Write to its data files. It also needs Read, Write, and Execute permissions set on any directories it will be creating files in. Usually, this involves its /data/ directory and any directories in which it will publish files.
The Unix program chmod is usually responsible for changing File Permissions; however, most FTP Clients have the ability to change File Permissions. Try right-clicking on a file and looking for a command such as "Change File Permissions", "Change File Attributes", or "chmod". The easiest way to specify Permissions is to enter the appropriate number in. Often programs will allow you to specify attributes via checkboxes, which isn't very useful if you already know what you want to set.