I'll have to check that in my sim, but from the screenshot, you have a total passenger weight of 27.100 pounds shown. So, despite the '0' entries, there seems to be a value which FSX takes into account.

Can you alter your weight settings in FSX to metric ones then restart FSX and change back to imperial? Maybe it changes something. I'd also go for deleting the current fsx.cfg and let the thing start from the scratch before thinking about reinstalling the whole bunch of addons.