Links to local pages do not work
From MozillaZine Knowledge Base
For security purposes, Firefox blocks links to local files from remote files by default. This includes linking to files on your hard drive or mapped network drives.
If you are willing to accept the possible risk of linking to local content, you can override the security policy. Type about:config into the address bar and hit [Enter]. Find the entry for security.checkloaduri and change its value to false by right-clicking it and choosing "Toggle". Then, restart Firefox.