Merge pull request #811 from normanjaeckel/Windows64bit

Update INSTALL. OpenSlides for Windows 64-bit (fixed #810).

INSTALL.txt

@@ -8,7 +8,7 @@ Content
 I.   Installation on GNU/Linux and MacOSX using the Python Package Index (PyPI)
 II.  Installation on GNU/Linux and MacOSX using the package from openslides.org
 III. Installation on GNU/Linux and MacOSX using the sources (for development)
-IV.  Installation on Windows (32bit) using the Python Package Index (PyPI)
+IV.  Installation on Windows using the Python Package Index (PyPI)
 
 If you need help ask on OpenSlides users mailing list.
 See http://openslides.org for more information.
@@ -160,7 +160,7 @@ III. Installation on GNU/Linux and MacOSX using the sources (for development)
         $ python start.py
 
 
-IV. Installation on Windows (32bit) using the Python Package Index (PyPI)
+IV. Installation on Windows using the Python Package Index (PyPI)
 =========================================================================
 
 NOTE: There is a portable version of OpenSlides for Windows which does not
@@ -174,10 +174,15 @@ portable version you should run the following install steps.
           + Python Programming Language 2 (>= 2.6)
           + Setuptools
 
-     a) Download and run 32bit MSI installer from http://www.python.org/:
+     a) Download and run 32-bit MSI installer from http://www.python.org/:
 
         http://www.python.org/ftp/python/2.7.5/python-2.7.5.msi
 
+        Note that the 32-bit MSI installer is required even on a 64-bit
+        Windows system. If you use the 64-bit MSI installer, step 3 of this
+        instruction will fail unless you installed the packages reportlab
+        and pillow manually.
+
      b) Add python dirs to PATH (via Control Panel > System > Advanced):
 
         ";C:\Python27;C:\Python27\Scripts"