[GRASS-user] Python script works with Qgis but not in Grass

Hello to everyone,

i got Windows 8 with QGIS Dofour 2.0.1 e Grass 6.4.3 on my PC.

I got no problem when i run my script on Qgis but i need to fix some problems inside it and Qgis doesn't show you any log errors so i need to use Grass.
When i launch it some errors happens:

Launching script 'C:\Program Files\QGIS Dufour\apps\grass\grass-6.4.3\etc\gui\scripts\v.grass2hec_rev.py'...
Exception in thread Thread-75:
Traceback (most recent call last):
   File
"C:\PROGRA~1\QGISDU~1\apps\Python27\lib\threading.py", line
808, in __bootstrap_inner
     self.run()
   File "C:\PROGRA~1\QGISDU~1\apps\grass\grass-6.4.3\etc\wxpy
thon\gui_core\goutput.py", line 126, in run
     self.resultQ.put((requestId, self.requestCmd.run()))
   File "C:\PROGRA~1\QGISDU~1\apps\grass\grass-6.4.3\etc\wxpy
thon\core\gcmd.py", line 553, in run
     env = env)
   File "C:\PROGRA~1\QGISDU~1\apps\grass\grass-6.4.3\etc\wxpy
thon\core\gcmd.py", line 164, in __init__
     subprocess.Popen.__init__(self, args, **kwargs)
   File
"C:\PROGRA~1\QGISDU~1\apps\Python27\lib\subprocess.py", line
711, in __init__
     errread, errwrite)
   File
"C:\PROGRA~1\QGISDU~1\apps\Python27\lib\subprocess.py", line
948, in _execute_child
     startupinfo)
TypeError: environment can only contain strings

First of all I uninstall and reinstall Qgis and Grass many times trying to understand if the problem was in the x86 version or in some registry forgot in the previous versions (i control the regedit deleting manually all the files i thought related to Qgis and Grass).
Then, i remembered that I installed Python one month ago (not in the same folder), then i uninstall it.
I fear to forgot some other registry but nothing is shown directly in the registry. All the Python27 are deleted.

Now i reinstall QGIS and Grass (version i told before) but still it doesn't work.

Really need a big help.