diff --git a/demo/viewer/SConscript b/demo/viewer/SConscript
index 94f07ee2f..ad30e7eb6 100644
--- a/demo/viewer/SConscript
+++ b/demo/viewer/SConscript
@@ -43,5 +43,5 @@ ini = ini_template % locals()
 open('viewer.ini','w').write(ini)
 
 try:
-    os.chmod(viewer.ini,0666)
+    os.chmod('viewer.ini',0666)
 except: pass