When I try to calulate collions I get an exception breakpoint error and cc3 closes.

I have tried it on 2 different pcs and im getting same error/crash

The crash is happening because of the green jacket. I an use the conform button on any other clothes and it works

You can also try reducing the density of the mesh. I always getting errors when the mesh is to highpoly.
I think this will fix the issue.

* Edit: After seeing your post I'm almost certain of it. Just reduce polycount of the coat.