bcrypt is breaking my meteor application, how do I fix it?

As of Meteor 1.0.5 (and this also applies to the forthcoming 1.1), we have not yet gone through the full testing, validation, and QA process with Node 0.12. I would recommend sticking with Node 0.10 until that point. While it is likely that it will mostly work, it's possible that some core changes will be necessary, and as you've seen, binary packages built against the 0.10 ABI don't work with 0.12.

The bcrypt module is platform dependant (as fibers), so you need to remove the package after decompressing the bundle in your server:

rm -R path/to/bcrypt

then install it again:

npm install bcrypt