Well, it isn't a bug, nor a crash, but a simple case of inability to start the game
Followed the download instructionst, installed first freelancer, then flmm, then crossfire. All seemed to work well, and crossfire is succesfuly enabled in flmm. Still, it doesn't work. The launcher downloaded its updates properly, but when I click on either single player or multiplayer nothing happens. The launcher closes and that's it.
Only change I've made to vanilla freelancer is tampering with it so that it works on my screen resolution, which is 1920x1080. But it worked fine before cf, and I can't see this interfering.
Maybe it's a Windows 7 issue? Or I've done something wrong, or haven't done something else?