Puck disconnecting after running function from the browser without passing a callback.

Could you check on the Web Browser's debug console and see if it really is just complaining about trying to call a callback that doesn't exist?

It wouldn't surprise me, and it's an easy fix - the standard Puck.write functions cope with not having callbacks fine, but I have to admit I have always used the connection-based write with a callback, so may not have added a check for when it doesn't exist.