The Titanium CLI isn't compatible with node 0.12 (TIMOB-18538). If you use homebrew and have already upgraded to 0.12, you can go back to 0.10.36 by running the following commands:
cd $( brew --prefix )
git checkout b64d9b9 Library/Formula/node.rb
brew unlink node
brew install node
You might want to use brew pin node
to keep brew upgrade
from updating that formula until the CLI is fixed.