Bah, stupid Windows version. It goes in ${HOME}/.fs2_open/data under Linux and OSX but the Windows version just has it in the same directory as the binary. Just move it and it should work fine.
The bug reports are deffinitely a help, though I am starting to wonder if you're just padding your post count.
The first Dunkerque crash where you are attacking the bombers looks to be hitting one of the first bugs you posted about, the model_get() crash. I added the extra NULL check there which is what it hit. That helps figure out where it's coming from but I still can't say that I know exactly why it happened. It looks to just be a problem with WMC's updated jumpnode code as it doesn't appear to handle model_load() errors very well but the rest of the code should have picked up the slack, at least in a debug build. I'll add an extra debug printout at the problem area and see if that can't help figure out what's going on. I'll try and reproduce as well but haven't been able to so far.