Actually this is confusing me as well.  Originally i had the problem with the plane not starting and windows not opening, so i could go online and it just wouldnt power up or move.  KBL [?] document suggested plane was in protected mode so uninstall and re-install with same order number. 

Joy plane powers up and flies fine offline, but as stated above it crashes FSX when you select the plane for online.

Even started multiplayer with another aircraft which started fine then selected change plane, as soon as the progress bar got to 6% it crashed FSX .  Tried this about 10 times so far.