New Javascript/JS errors after installing Fooman Speedster

If you€'™re seeing new Javascript (JS) errors that were not present before installing Fooman Speedster, these are most likely caused by either trying to minify already minified files, or minifying Javascript files that do not follow best practice coding style for Javascript. 

To fix the double minification problem, replace the already minified file with the original non-minified Javascript. A Javascript file with .min.js in its file name is always a sure sign that this file has been minified. To find the origin of remaining Javascript errors, we suggest testing all Javascript files which are not part of the Magento base/default theme on www.jslint.com for code quality.