Python module not found (directory problems)
Question: I have a Python 2.5 project with following directory structure:

    
    
    database/__init__.py
    database/createDBConnection.py
    gui/mainwindow.py
    

When I try to run

    
    
    python gui/mainwindow.py
    

I get the error

    
    
    C:\PopGen>python gui/mainwindow.py
    Traceback (most recent call last):
      File "gui/mainwindow.py", line 12, in <module>
        from database.createDBConnection import createDBC
    ImportError: No module named database.createDBConnection
    

In mainwindow.py, there is following statement on line 12

    
    
    from database.createDBConnection import createDBC
    

The problem occurs because Python can't find the database module.

Question: What can I do in order to fix this error?

Here's the code of the project:
<https://www.dropbox.com/sh/edfutlba960atp9/MwFpaepEpl>

I tried to use

    
    
    C:\PopGen>python -m gui.mainwindow
    

but got these errors

    
    
    Traceback (most recent call last):
      File "C:\Python25\lib\runpy.py", line 95, in run_module
        filename, loader, alter_sys)
      File "C:\Python25\lib\runpy.py", line 52, in _run_module_code
        mod_name, mod_fname, mod_loader)
      File "C:\Python25\lib\runpy.py", line 32, in _run_code
        exec code in run_globals
      File "C:\PopGen\gui\mainwindow.py", line 13, in <module>
        from file_menu.wizard_window_validate import Wizard
    ImportError: No module named file_menu.wizard_window_validate
    


Answer: There are several ways to fix this, but this is perhaps the easiest one.

Try adding this in mainwindow.py, prior to the import that is failing:

    
    
    import sys
    sys.path.append("C:/path/to/database/module")
    

