("[Errno 2] No such file or directory: 'TMPDIR=tmp'", )

Hi I’m having troubles with the demo courses,

Hi. Did you modify the block?
The error message mentions the „script code“. You can inspect what’s that script’s code, clicking EDITAR and seeing whether there’s something written there that is trying to access files. For instance, when I tried it, I saw a <script type="loncapa/python"> section with Python code.

It may be that Open edX isn’t correctly installed and doesn’t have access to a /tmp directory.
You can provide more details about how you installed it.

I think the easiest solution is to experiment more, in many ways: for instance: try to add a new „molecule editor“ yourself, and see what happens. Try to compare a broken block vs. a working block. Find other blocks which are failing, etc.

You may also try exporting the course, to inspect it in more detail.