The absolute path is the directory location on a server's hard drive where Joomla! is located. It can vary depending on your server type.
To find out what your absolute path is, copy the following code into a text editor (i.e. JEdit, Notepad, etc), save the file as a .php naming it whatever you prefer (i.e anyfilename.php.).
$path = getcwd();
echo "Your Absoluthe Path is: ";
Using your FTP software, ftp the file you have just created to your root folder.
Open your web browser and type in http://www.yourdomain.com/filename.php. The result will show the absolute path!
IMPORTANT: For security reasons, delete this file as soon as you have ascertained the information you require.