Graph Composer 2.0.0 v4l2src - TypeError - Docker workflow option

Attempting to create a simple pipeline in GC sing a USB camera (logitech brio) (have developed the same in python and successfully used with trained TAO model).

Review GTC22 Video regarding getting started and created a v4l2src using the generate extension. Added component to graph but will not run. Below errors

2022-05-24 21:43:52 [Error] [asyncio] [/tmp/.tmpNvXgRaphComposer/run/kit/python/lib/python3.7/asyncio/base_events.py:1619] Task exception was never retrieved
2022-05-24 21:43:52 [Error] [asyncio] future: <Task finished coro=<RunGraphWindow.async_on_run_clicked() done, defined at /tmp/.tmpNvXgRaphComposer/run/composer/omni.exp.graph.composer/omni/exp/graph/composer/run_graph_window.py:356> exception=TypeError(‘can only concatenate str (not “NoneType”) to str’)>
2022-05-24 21:43:52 [Error] [asyncio] Traceback (most recent call last):
2022-05-24 21:43:52 [Error] [asyncio] File “/tmp/.tmpNvXgRaphComposer/run/composer/omni.exp.graph.composer/omni/exp/graph/composer/run_graph_window.py”, line 359, in async_on_run_clicked
2022-05-24 21:43:52 [Error] [asyncio] self._logger.info("Running graph " + self._graph_path)
2022-05-24 21:43:52 [Error] [asyncio] TypeError: can only concatenate str (not “NoneType”) to str

It does not matter what components I add after - it always fails with same error.

Any help gratefully received.

Cheers