Weird, the 2.00 version from Packal doesn seem to work on OS X 10.7.5 ... I checked the workflow folder and the "Colors.app" inside requires OS X 10.8 or later., so it is blocked. Is that the problem ? Version 1.41 works fine for me though.
Edit : I've tested the "colors" executable, run in Terminal
sudo dtruss ./colors '#8a2be2'
and gotten the following error
failed to execute ./colors: Could not create symbolicator for task
This seems to be this bug that prevent the 2.00 version of the worflow from working on my machine. Can anyone help me on this ?
Meanwhile, I also replaced the "Colors.app" by the one I found on http://mattpatenaude.com/, if that might help.