Showstoppers when flying at night time

Hi folks, After having enjoyed a couple of flights at daytime with everything working as it should, I just ran into lots of problems when flying at night. - First thing I noticed was that the TRANS ALT defaults to 17000ft, although I had set this to 5000 via the PMDG menu in the CDU.- The strobe lights don't seem to work.- Once I was ready for taxi, the throttles on my joystick didn't respond, neither did the engines displays. They were "frozen" at 31% N1. Changing thrust via the F3 key worked, but the displays were still frozen. So, I restarted FSX, tried again, but: - Still 17000ft TRANS ALT- Still no strobes- This time, I was able to taxi to the holding point, but when I tried to stop, the thrust lever on my joystick failed to work again, and I could not steer the nose wheel via my joystick's z-axis any more. I didn't have any of these issues at daytime. Did anyone experience similar problems at night or has anyone have an idea what's wrong here? Thanks in advance.