Don't crash when sys.path contains an empty string.
diff --git a/Tools/idle/PathBrowser.py b/Tools/idle/PathBrowser.py
index d8f5b55..b24977f 100644
--- a/Tools/idle/PathBrowser.py
+++ b/Tools/idle/PathBrowser.py
@@ -49,7 +49,7 @@
             return self.listmethods()
     
     def listmodules(self):
-        dir = self.path[0]
+        dir = self.path[0] or os.curdir
         modules = {}
         suffixes = imp.get_suffixes()
         allnames = os.listdir(dir)