Installing an extension
From Joomla! Documentation
Before starting it always is wise to read the documentation associated with an extension. Most extensions have homepages and forums. Look at them first. If there is a README file included with the extension, you should read it.
For most extensions and most users, the procedure will be:
- Download the extension to your local machine as a .zip file package.
- From the Backend of your Joomla site (Administrator) select Extensions → Install/Uninstall.
- Click the Browse button and select the extension package on your local machine.
- Click the Upload File & Install button.
- Some extensions may provide further instructions on installation.
- Note that modules and plugins must be enabled before they will work.
There are some situations in which this procedure will not work.
Sometimes you need to unzip the file locally prior to installing. If you get an error saying that the file is not in the correct format, the need to unzip is a common cause of this. After unzipping try installing the individual items. Note that the files you upload using the installer still need to be zipped.
Sometimes you cannot use the automated installer. For example, very large extensions may exceed the maximum upload size allowed by your host.
Also, If you see an error like this:
Warning: is_dir() [function.is-dir]: open_basedir restriction in effect. File(/) is not within the allowed path(s): ...
there is a restriction in your hosting account which leads Joomla! to try to check if the root directory exists. You will not be able to use the automated installer.
First, unzip all of the files in a local directory (for instance com_installer). Then transfer the directory (using FTP) to a folder under the install directory (for instance administrator/components), appropriate for the type of extension you are installing (visible in its XML file, a line like <extension type="component" ...). Then use the installer, but select install from directory indicating the correct folder name. This folder name should be an absolute path from the root of the file system.