Comment 32 for bug 526482

(To be clear, Olli is pointing out that you need to update the hexadecimal UUID here to a new randomly-generated UUID:
  https://mxr.mozilla.org/mozilla-central/source/widget/nsIPrintSettings.idl#25
since the interface is changing. Sorry, I should've caught that when I first looked at this.)

There's a variety of ways to generate UUIDs; one easy way is to just say "firebot, uuid" on irc.mozilla.org. (by e.g. visiting http://irc.lc/mozilla/firebot/yourIRCUsername)