Graphviz error if ZIM started in shell

[Rich Trefz]

Win7 x64
ZIM 0.59
Graphviz-2.30.1

I installed to C:\programs\x86\ZimDesktopWiki\
I started cmd. Dot is in path
    >where dot
    C:\programs\x86\Graphviz2.30\bin\dot.exe

ZIM runs OK. Under Edit -> Preferences -> Plugins -> Insert diagram
Dependencies
• GraphViz - OK

After creating / editing a diagram, I get
An error occurred while generating the image.
Do you want to save the source text anyway?

If I start ZIM from desktop shortcut, Graphviz works OK.

---------------------------------------------------------------------------------------

INFO: Starting async index update
INFO: Open page: <FileStorePage: Home> (<HistoryPath: Home>)
WARNING: No such image: C:\Users\rich\Notebooks\Notes\Home\diagram.png
IINFO: Last child quit, stopping server
DEBUG: Server stopped listening
INFO: Remove file: c:\temp\rich\zim-rich\zim-server-authkey
DEBUG: Server process 4444 quit
DEBUG: Server thread for process 1172 quit
File "zim\gui\widgets.pyo", line 3977, in set_file
GError: Failed to open file 'C:\Users\rich\Notebooks\Notes\Home\diagram.png': No such file or directory
INFO: Running: ['dot', '-Tpng', '-o', 'c:\\temp\\rich\\zim-rich\\diagram.png', 'c:\\temp\\rich\\zim-rich\\diagram.dot'] (cwd: None)
ERROR: Could not generate image
Traceback (most recent call last):
  File "zim\gui\imagegeneratordialog.pyo", line 210, in generate_image
  File "C:\programs\x86\ZimDesktopWiki\zim\plugins\diagrameditor.py", line 110, in generate_image
  File "zim\applications.pyo", line 168, in run
  File "subprocess.pyo", line 672, in __init__
  File "subprocess.pyo", line 787, in _get_handles
  File "subprocess.pyo", line 826, in _make_inheritable
WindowsError: [Error 6] The handle is invalid
INFO: Open page: <FileStorePage: Home> (<FileStorePage: Home>)
WARNING: No such image: C:\Users\rich\Notebooks\Notes\Home\diagram.png
INFO: Remove file: c:\temp\rich\zim-rich\diagram.dot
INFO: Remove file: c:\temp\rich\zim-rich\diagram.png

[Jaap Karssenberg (jaap.karssenberg)]

Looks like this is the same issue: http://bugs.python.org/issue3905

INvestigated, but so I see no hints how to work around :(