diff --git a/Tools/buildbot/external.bat b/Tools/buildbot/external.bat
index 39c118197a9..1b032aecffc 100644
--- a/Tools/buildbot/external.bat
+++ b/Tools/buildbot/external.bat
@@ -2,6 +2,7 @@
 
 @rem Assume we start inside the Python source directory
 cd ..
+call "%VS71COMNTOOLS%vsvars32.bat"
 
 @rem bzip
 if not exist bzip2-1.0.3 svn export http://svn.python.org/projects/external/bzip2-1.0.3