Hey Uprentiss,
Sorry about this. Someone else above mentioned the same issue and the problem is with the Lightmap resolution on some of the assets being too high. If you check out my comment from 2-27-2015 at 11:44am I mention how you can go about fixing this and you can see in the posts above others mentioning the crash after rebuilding the lighting. I apologize that I didn’t catch this issue with the Lightmap resolution on the assets sooner. I did my best to try to check everything before checking in the updated Building Set, but unfortunately this one thing slipped passed me. Luckily it’s easy enough to fix the issue and I definitely plan on updating this for everyone so this won’t be an issue that everyone runs into. But you know how the updates go…