import problem

_transforms import Value, Point, Bbox, Affine

    > ImportError: No module named _transforms

Most likely you are trying to run matplotlib in the dir you installed
it in. Switch to a different directory and try again. If you run
from the same dir that matplotlib is installed in, you can only see
the python files and not the extension code (eg _transforms)

    > It is weird because it is working the second time I try
    > the same import but as you can see, it seems that "plot"
    > is not recognized after all.

This is normal. When you try and import a package a second time after
it has already failed, nothing happens (no error the second time).
This doesn't tell you anything useful though.

Your best bet is to cd into the matplotlib examples dir and try

  > python

and see if this works.

Good luck!