Fix lib-tk PythonPath.
diff --git a/Tools/msi/msi.py b/Tools/msi/msi.py
index fa2a9fc..cda7bb6 100644
--- a/Tools/msi/msi.py
+++ b/Tools/msi/msi.py
@@ -1085,7 +1085,7 @@
               ("InstallGroup", -1, prefix+r"\InstallPath\InstallGroup", "",
                "Python %s" % short_version, "REGISTRY"),
               ("PythonPath", -1, prefix+r"\PythonPath", "",
-               "[TARGETDIR]Lib;[TARGETDIR]DLLs;[TARGETDIR]lib-tk", "REGISTRY"),
+               r"[TARGETDIR]Lib;[TARGETDIR]DLLs;[TARGETDIR]Lib\lib-tk", "REGISTRY"),
               ("Documentation", -1, prefix+r"\Help\Main Python Documentation", "",
                r"[TARGETDIR]Doc\Python%s%s.chm" % (major, minor), "REGISTRY"),
               ("Modules", -1, prefix+r"\Modules", "+", None, "REGISTRY"),