Firefox 25 on OSX gives me: The address wasn't understood Firefox doesn't know how to open this address, because the protocol (site) isn't associated wi

Firefox 25 on OSX gives me: The address wasn't understood Firefox doesn't know how to open this address, because the protocol (site) isn't associated with any program. You might need to install other software to open this address. Firefox 21 on Ubuntu was giving me the same thing, I don't think I've tried it on Firefox 25 on my Ubuntu install.