This has been reported by one of our customers. The problem with FF 3.x seems to be related to the synchronous call to the server we make in softLocking.js#getSoftLockingConfiguration() on loading the page in order to check whether soft locking is enabled or not. This call does not seem to work, that is the function returns immediately (as if it were asynchronous) and the return value is undefined, hence the js error. We need to investigate if this is a known issue with FF 3.x (later versions behave in the expected way) and see if there's a workaround for it.