Hi
The problem is that your copy of node or npm is installed in .npm-global in your home directory instead of somewhere like /usr/local and /Users/<your_username>/.npm-global/bin is not in your PATH, so bash can’t find it.
Please have a look at this thread where another user had the same problem.
In theory, adding the ~/.npm-global/bin to the start of your PATH in ~/.profile should do the trick (after a restart of the Terminal so that bash (running in the Terminal) can re-read the .profile). But for a reason I was not able to figure out that did not work for the user who posted the above mentioned thread. So the sledgehammer is to add the path to /etc/paths.