Updates:
Status: Invalid
Comment #3 on issue 598 by pekka.klarck: import problem in Testdoc and
libdoc tools in robotframework-2.5
http://code.google.com/p/robotframework/issues/detail?id=598
Having multiple RF versions installed ought to work fine if you just have the right RF version first in PYTHONPATH when you run libdoc.py/testdoc.py.
