I have a problem.

When I start LMMS and open settings, it says sound is set to Dummy.
I change it from Dummy to Port Audio, and LMMS predictably tells me these changes won't take effect until LMMS is restarted.
I close LMMS down and start it up again, and LMMS is back to being on Dummy again!

What do I need to do to fix this???