Aditya Mahajan
This means that write18 is disabled on your system, so tex cannot execute any system commands. This is a security feature and most intallation disable write18 by default. You need to edit your texmf.cnf file to enable it. Search for texmf.cnf using
texmfstart --locate texmf.cnf
open that file in your favourite editor.
Search for shell_escape and set it to true by
shell_escape = t
This worked for enabling the commands. Of course, this revealed a new problem. texmfstart was not being called correctly. Replacing texmfstart with: ruby /usr/local/teTeX/share/texmf.local/scripts/context/ruby/texmfstart.rb , which is my path to texmfstart.rb, in \runR solved the problem. I had followed the "Other method" from the ConTeXt wiki for enabling texmfstart on my system. This works fine for calling commands from the command line, but (as suggested in the wiki) doesn't necessarily work for other methods. Once I sort out all of these OS X specific details, I'll post back to my original message with a solution. Thanks, Matt