It's been ages since I've done anything Drupal. But I needed to move an old site to a new host. (We're moving it to Pantheon, which rocks!)
I fired up trusty old MAMP Pro 2.2 and... whaaaa??? Apache can't start!
Quick Google of the situation and I found an easy solution:
Just go to /Applications/MAMP/bin/apache2/bin in your Finder and rename envvars to _envvars. That's it. All done.
Now back to work.