bad marshal data in site.py in fresh 2.5 install win

[TiNo]

Hi,

I have installed python two days ago on a USB memory stick (I am on
the move and have no laptop.) I am on windows computers, mostly XP,
all the time.

Now, after pluging it in to a different computer, I get the following
message when I run pyhthon:
'import site' failed; use -v for traceback

python -v gives:
------------------------------------------------------------------------
G:\Python25>python -v
# installing zipimport hook
import zipimport # builtin
# installed zipimport hook
# G:\Python25\lib\site.pyc matches G:\Python25\lib\site.py
import site # precompiled from G:\Python25\lib\site.pyc
# G:\Python25\lib\os.pyc matches G:\Python25\lib\os.py
import os # precompiled from G:\Python25\lib\os.pyc
import nt # builtin
# G:\Python25\lib\ntpath.pyc matches G:\Python25\lib\ntpath.py
import ntpath # precompiled from G:\Python25\lib\ntpath.pyc
# G:\Python25\lib\stat.pyc matches G:\Python25\lib\stat.py
import stat # precompiled from G:\Python25\lib\stat.pyc
# G:\Python25\lib\UserDict.pyc matches G:\Python25\lib\UserDict.py
import UserDict # precompiled from G:\Python25\lib\UserDict.pyc
# G:\Python25\lib\copy_reg.pyc matches G:\Python25\lib\copy_reg.py
import copy_reg # precompiled from G:\Python25\lib\copy_reg.pyc
# G:\Python25\lib\types.pyc matches G:\Python25\lib\types.py
import types # precompiled from G:\Python25\lib\types.pyc
import _types # builtin
# zipimport: found 74 names in G:\Python25\lib\site-packages\setuptools-0.6c3-py
2.5.egg
# G:\Python25\lib\locale.pyc matches G:\Python25\lib\locale.py
import locale # precompiled from G:\Python25\lib\locale.pyc
import encodings # directory G:\Python25\lib\encodings
# G:\Python25\lib\encodings\__init__.pyc matches G:\Python25\lib\encodings\__ini
t__.py
import encodings # precompiled from G:\Python25\lib\encodings\__init__.pyc
# G:\Python25\lib\codecs.pyc matches G:\Python25\lib\codecs.py
import codecs # precompiled from G:\Python25\lib\codecs.pyc
import _codecs # builtin
# G:\Python25\lib\encodings\aliases.pyc matches G:\Python25\lib\encodings\aliase
s.py
'import site' failed; traceback:
Traceback (most recent call last):
  File "G:\Python25\lib\site.py", line 415, in <module>
    main()
  File "G:\Python25\lib\site.py", line 406, in main
    aliasmbcs()
  File "G:\Python25\lib\site.py", line 356, in aliasmbcs
    import locale, codecs
  File "G:\Python25\lib\locale.py", line 14, in <module>
    import sys, encodings, encodings.aliases
  File "F:\Python25\lib\encodings\__init__.py", line 32, in <module>
ValueError: bad marshal data
# G:\Python25\lib\warnings.pyc matches G:\Python25\lib\warnings.py
import warnings # precompiled from G:\Python25\lib\warnings.pyc
# G:\Python25\lib\linecache.pyc matches G:\Python25\lib\linecache.py
import linecache # precompiled from G:\Python25\lib\linecache.pyc
Python 2.5 (r25:51908, Sep 19 2006, 09:52:17) [MSC v.1310 32 bit (Intel)] on win
32
Type "help", "copyright", "credits" or "license" for more information.
>>>
---------------------------------------------------------

What can I do about this?

Thanks,

TiNo