You started the install of the latest Joomla version and the installation stops because the "Magic Quotes GPC Off" didnt pass the pre-install checks did it?
This is a simple fix.
Step 1) Create a php.ini file and place the following code into it.
magic_quotes_gpc = Off
session.save_path = "/tmp"
Step 2) Once you have created the file, stick the php.ini file in the "Installation Folder". Not the root but in the public_html/installation/ location.
Once you have placed the php.ini file in the installation folder, go back to the setup and hit the "check again" button. You should pass the test and move on to the next screen.