Upgraded Ti Studio - now cannot build and run - help!

I have been keeping Ti Studio up-to-date with the latest releases as they come out. This morning a new version update message came up in Studio - so I updated as per usual.

Ti Studio restarted.

I got a message about node.js requiring a new version - so I upgraded to 0.8.6 and restarted Ti Studio. All ok.

But when I try to build for the iPad Simulator I get the following:

Traceback (most recent call last):
  File "/Library/Application Support/Titanium/mobilesdk/osx/2.1.1.GA/iphone/builder.py", line 1604, in <module>
    main(sys.argv)
  File "/Library/Application Support/Titanium/mobilesdk/osx/2.1.1.GA/iphone/builder.py", line 570, in main
    ensure_dev_path()
  File "/Library/Application Support/Titanium/mobilesdk/osx/2.1.1.GA/iphone/tools.py", line 8, in ensure_dev_path
    rc = subprocess.call(["xcode-select", "-print-path"], stdout=open(os.devnull, 'w'), stderr=open(os.devnull, 'w'))
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/subprocess.py", line 493, in call
    return Popen(*popenargs, **kwargs).wait()
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/subprocess.py", line 679, in __init__
    errread, errwrite)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/subprocess.py", line 1228, in _execute_child
    raise child_exception
OSError: [Errno 2] No such file or directory

I am on Mountain Lion. Was building fine yesterday. I have cleaned out the Project and re-run the build process - same error.

Please help me resolve this as I am in the middle of finalising an update for my app.

Thanks,

Matt