I had the same problem described here: Can't find TikZ library calc
However, when I tried to follow the instructions in the answer to that question I got
sudo: tlmgr: command not found
I'm using a Mac. Any suggestions?
I also tried downloading TikZ 2.10 and using texhash as described here How to install a current version of TikZ? but that didn't solve the problem.
macportssometimes has. – Dror Oct 23 '12 at 6:14