Files required for Morfa-C (in order of installation):

 * n_, v_, a_, pron_, prop_
 * fillings
 * tags.txt
 * questions.xml



Common errors: 

 * not task: means that the Question/QElement objects have been installed, but during the installation process Words or Forms matching the tag semantic type may not have been located.
 > Solution: check that forms are being generated, check that words can be found with that semantic type.

 * Database not properly loaded.
 Two possible solutions: 
  * There are no questions installed of this type
  * The type does not exist in forms.py, and the code cannot handle the type listed. 
 	 	 

 * IndexError

 * Random (0, 0, 0) error

 * SUBJ appearing

 * MAINV appearing