TypeError: 'NoneType' object is not subscriptable

[chowell@…]

How to Reproduce

While doing a GET operation on /burndown, Trac issued an internal error.

I downloaded and installed the plugin via easy_install and giving the SVN location as specified on the page.

This is what I did:

C:\>easy_install http://trac-hacks.org/svn/scrumburndownplugin/
Downloading http://trac-hacks.org/svn/scrumburndownplugin/
Doing subversion checkout from http://trac-hacks.org/svn/scrumburndownplugin/ to
 c:\docume~1\admini~1\locals~1\temp\easy_install-aonx7g\scrumburndownplugin
Processing scrumburndownplugin
Running trunk\setup.py -q bdist_egg --dist-dir c:\docume~1\admini~1\locals~1\tem
p\easy_install-aonx7g\scrumburndownplugin\trunk\egg-dist-tmp-vk_ngq
zip_safe flag not set; analyzing archive contents...
Adding tracburndown 1.9.2 to easy-install.pth file

Installed c:\python27\lib\site-packages\tracburndown-1.9.2-py2.7.egg
Processing dependencies for tracburndown==1.9.2
Finished processing dependencies for tracburndown==1.9.2

C:\>trac-admin C:\trac\poc upgrade
Attempting to create the burndown table
Attempting to modify the milestone table
Upgrade of the Burndown plugin failed
Error message: (1264, "Out of range value for column 'due' at row 1")
Upgrade done

As you can see after running my environment upgrade I encountered this issue shown above.

When I tried to use the plugin via Trac get: TypeError: 'NoneType' object is not subscriptable.

Please see below for environment setting and python traceback. I have also attached my log file. Please advise.

Request parameters:

{}

User agent: Opera/9.80 (Windows NT 5.2; U; en) Presto/2.8.131 Version/11.10

System Information

Trac	0.12.3dev-r10683
Babel	0.9.5
FullBlog	0.1.1-r9430
Genshi	0.6
mod_wsgi	3.3 (WSGIProcessGroup WSGIApplicationGroup %{GLOBAL})
MySQL	server: "5.5.11", client: "5.1.50", thread-safe: 1
MySQLdb	1.2.3
Python	2.7.1 (r271:86832, Nov 27 2010, 18:30:46) [MSC v.1500 32 bit (Intel)]
RPC	1.1.2-r9970
setuptools	0.6c11
jQuery	1.4.4

Enabled Plugins

duplicateticketsearch	1.0.1
estimatorplugin	0.2.5
timingandestimationplugin	1.1.3b
tracburndown	1.9.2
tracdiscussion	0.8-r9877
tracexcelviewer	0.1
tracfullblogplugin	0.1.1-r9430
tracsectioneditplugin	0.1.1
tractags	0.6
tracvote	0.1.3
tracwysiwyg	0.12.0.3-r9676
tracxmlrpc	1.1.2-r9970

Python Traceback

Traceback (most recent call last):
  File "build\bdist.win32\egg\trac\web\main.py", line 517, in _dispatch_request
    dispatcher.dispatch(req)
  File "build\bdist.win32\egg\trac\web\main.py", line 238, in dispatch
    resp = chosen_handler.process_request(req)
  File "build\bdist.win32\egg\burndown\burndown.py", line 172, in process_request
    data['burndown_data'] = req.hdf['burndown_data'] = self.get_burndown_data(db, selected_milestone, components, selected_component)
  File "build\bdist.win32\egg\burndown\burndown.py", line 205, in get_burndown_data
    cursor.execute(sqlBurndown, (selected_milestone['name'], comp['name']))
TypeError: 'NoneType' object is not subscriptable