On file and directory permission and ownership
From Online Manual
Installing SMF Packages requires either editing files or adding files and/or directories. Changing a file means reading a file and replacing it with a changed version of the file. All of Package Manager's changes to SMF's software require the permissions to read from, and write to, files and directories. Sometimes, package installation fails because of file permission problems. This page explains some of the common problems and offers some guidance on resolving them.
File Permissions and Ownership
On Unix-based systems, file permissions are changed using a utility called chmod. FTP servers generally provide a local command, also called chmod, to allow setting file permissions via FTP. If you are using an old style command-line FTP client, you will have to use this command directly, but if you are using one of the popular drag-and-drop style FTP clients (like FileZilla, cuteFTP), you will be able to view and change file permissions by checking and changing the properties of the files. If your web host provides it, you may be able to log in directly to the account using SSH and explore your files using Unix shell commands.
You should be able to change the permissions of files you own, but you might not own all the files that you think you do. It may be the case that some of the files in your directories might belong to another user. Some FTP clients do not give you information about file ownership. On Unix-based operating systems, the chown utility is used to change file ownership.
To learn more about navigating your files using FTP, please read How do I use FTP. To find out if your host provides SSH access to your account, check your host's website or contact their technical support.