OSError: [Errno 2] No such file or directory

Whenever I try to compile the code, I get the error "OSError: [Errno 2] No such file or directory"
Here is the terminal output:

cabox@box-codeanywhere:~/workspace$ python ./build.py
Writing index.html...
Minifying...
  + src/jquery.hotkeys-0.7.9.js
Traceback (most recent call last):
  File "./build.py", line 73, in <module>
    build("src", "build")
  File "./build.py", line 56, in build
    stdout=mini_file)
  File "/usr/lib/python2.7/subprocess.py", line 522, in call
    return Popen(*popenargs, **kwargs).wait()
  File "/usr/lib/python2.7/subprocess.py", line 710, in __init__
    errread, errwrite)
  File "/usr/lib/python2.7/subprocess.py", line 1327, in _execute_child
    raise child_exception
OSError: [Errno 2] No such file or directory

(Yes, I am using CodeAnywhere)