Step 2 - Verify Permission Settings
To verify that you have the correct permission settings to run Fooman Speedster, visit the url: http://YOURMAGENTOWEBSITE/lib/minify/m.php (be sure to adapt the url to include your own domain).
This test should return a blank page with only these words:
“HTTP/1.0 404 Not Found”.
If you see this message, permission settings are working correctly and you can move to the next verification test.
If you do not see this message:
Internal Server Error Message
The most common error message you will see is the “Internal Server Error” message, which is caused by incorrect permission settings. Change your permission settings to allow the file to be executed by the web server. Apply the same setting to the folder /lib/minify and the file m.php.
Note: Permission requirements differ from server to server, but most often permissions 755 or 775 will work. If in doubt, check which permissions are working for your main index.php in the Magento root folder.
Magento 404 Error Message (Fully Styled)
If redirected to Magento's fully styled, '404 Page Not Found' page, this indicates a permission issue. Please contact your Server Administrator or Hosting company to determine why the file is not accessible to you.
Other Error Messages
If you encounter any other error messages, consult your server's error log for clues about the error source and refer to the appropriate troubleshooting step in this Help Centre.