TypeError: cannot return std::string from Unicode object on milestone select

[Jay]

When clicking on a milestone from the dashbord, I get the following error.

TypeError: cannot return std::string from Unicode object

with the following traceback: file attached, its a long one.

on install I noticed the following warnings:

C:\usr\bin\Python25\lib\site-packages\matplotlib\__init__.py:753: UserWarning:  This call to matplot
lib.use() has no effect
because the the backend has already been chosen;
matplotlib.use() must be called *before* pylab, matplotlib.pyplot,
or matplotlib.backends is imported for the first time.

  warnings.warn(_use_error_msg)
TracMetrix Plugin needs an upgrade
creating cache folder
Done Upgrading
Upgrade done.

but ignored it

and here is my system info trac .11 windows with tracd

User Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.13) Gecko/20080311 Firefox/2.0.0.13
Trac: 	0.11b2
Python: 	2.5.2 (r252:60911, Feb 21 2008, 13:11:45) [MSC v.1310 32 bit (Intel)]
setuptools: 	0.6c7
SQLite: 	3.3.4
pysqlite: 	2.3.2
Genshi: 	0.5dev-r826
Subversion: 	1.4.6 (r28521)
jQuery:	1.2.3

[Jay]

traceback copy

[Bhuricha Deen Sethanandha]

What matplotlib version are you using?

[Richard Wall]

Closing as duplicate of #2504 (the warning log message is related to #3248)