I just did:
export PYTHONPATH=$PYTHONPATH:/usr/lib/x86_64-linux-gnu/root5.34
and
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/lib/x86_64-linux-gnu/root5.34
And that problem is solved. Thank you.
(Although it now shows another error compiling the file sources for SampleAnalyzer library. 
)