Hi Danish,
Welcome to moodle.org.
Moodle is open source software, and moodle.org is the place where many of the people involved in developing and using Moodle get together to discuss problems and ask questions about running courses and sites using Moodle.
Perhaps you could try speaking to someone in the school, or possibly the company who appears to be hosting this on behalf of your school - schoolanywhere.co.uk.
Oh, and btw - why did you uploading a small javascript file, containing the following text:
pref("xpinstall.enabled", true);
pref("xpinstall.whitelist.required", true);
--
Sean Farrell