On OS X 10.11.2 - Sublime Text 3
I have the htmlbeautifier gem (1.1.1) properly installed. From the terminal htmlbeautifier my_file.html.erb works as expected and beautifies the file.
The plugin is installed (via package control) and works for standard ruby (.rb) files.
However the I get the 'Error: invalid output. Check your ruby interpreter setting' error whenever I try to beautify a .erb file within Sublime.
Any ideas?