Using TkInter as gui, running a module that worked in 3.0 (I believe). 

It is trying to print a warning message about 

RuntimeWarning: overflow encountered in double_scalars

and stops my process (running eval) returning this error

  File "C:\Python32\lib\idlelib\PyShell.py", line 59, in idle_showwarning
    file.write(warnings.formatwarning(message, category, filename,
AttributeError: 'NoneType' object has no attribute 'write'

If I use python -m idlelib.idle it doesn't happen; it just prints the error.

Previously this worked fine using the shell as stdout. This is similar to a bug about symbols' errors however it has been closed and this one is not about symbols. http://bugs.python.org/issue14200

I don't really know a lot about programming and don't often submit bugs so sorry if I've missed any major details here.

Marc