diff --git a/Contrib/Math/SConscript b/Contrib/Math/SConscript
index b1ea36b1..5ed66e17 100644
--- a/Contrib/Math/SConscript
+++ b/Contrib/Math/SConscript
@@ -23,7 +23,7 @@ docs = Split("""
 
 Import('BuildPlugin env')
 
-if float(env['MSVS_VERSION'].replace('Exp','')) >= 8.0:
+if env.has_key('MSVS_VERSION') and float(env['MSVS_VERSION'].replace('Exp','')) >= 8.0:
 	files += ['Source/mathcrtmt.lib']
 else:
 	files += ['Source/mathcrt.lib']