python之没有名为 "myapp"的模型，即使我在 settings.py 中添加了它

我收到以下错误:

ImportError at / 
No module named midi_app 
Request Method: GET 
Request URL:    http://127.0.0.1:8000/ 
Django Version: 1.4.1 
Exception Type: ImportError 
Exception Value:    No module named midi_app 
Exception Location: /Users/home/virtualenv/venv/lib/python2.7/site-packages/django/utils/importlib.py in import_module, line 35 
Python Executable:  /Users/home/virtualenv/venv/bin/python 

我已将我的应用“midi_app”添加到 settings.py 中的 INSTALLED_APPS 部分。我不确定为什么会看到此错误。 virtualenv 与它有什么关系吗？

谢谢。

更新:我已经添加了尽可能多的目录，但我仍然看到这个错误。请在下面查看我的路径。请帮忙，我真的很沮丧。

'/Users/home/virtualenv/venv/lib/python27.zip',

'/Users/home/virtualenv/venv/lib/python2.7',

'/Users/home/virtualenv/venv/lib/python2.7/plat-darwin',

'/Users/home/virtualenv/venv/lib/python2.7/plat-mac',

'/Users/home/virtualenv/venv/lib/python2.7/plat-mac/lib-scriptpackages',

'/Users/home/virtualenv/venv/lib/python2.7/lib-tk',

'/Users/home/virtualenv/venv/lib/python2.7/lib-old',

'/Users/home/virtualenv/venv/lib/python2.7/lib-dynload',

'/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7',

'/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/plat-darwin',

'/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/lib-tk',

'/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/plat-mac',

'/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/plat-mac/lib-scriptpackages',

'/Users/home/virtualenv/venv/lib/python2.7/site-packages',

'/Users/home/Desktop/Web Development/Django-1.4',

'/Users/home/virtualenv/venv',

'/Users/home/Desktop/Web Development/Aptana Studio 3.0',

'/Users/home/virtualenv/venv/bin',

'/Users/home/Desktop/Web Development',

'/Users/home/virtualenv',

'/Users/home/virtualenv/venv/lib/python2.7/site-packages/PIL',

'/Users/home/virtualenv/venv/lib/python27.zip',

'/Users/home/virtualenv/venv/lib/python2.7/plat-darwin',

'/Users/home/virtualenv/venv/lib/python2.7/plat-mac',

'/Users/home/virtualenv/venv/lib/python2.7/plat-mac/lib-scriptpackages',

'/Users/home/virtualenv/venv/lib/python2.7/lib-tk',

'/Users/home/virtualenv/venv/lib/python2.7/lib-old'

请您参考如下方法:

原来我的网址是错误的。

我把它指定为

url(r'^$', 'musicproject.midi_app.views.index'), 

代替

 url(r'^$', 'midi_app.views.index'), 

感谢您的帮助。