The usual...
diff --git a/Lib/dos-8x3/macurl2p.py b/Lib/dos-8x3/macurl2p.py
index 7d273bc..c971eda 100755
--- a/Lib/dos-8x3/macurl2p.py
+++ b/Lib/dos-8x3/macurl2p.py
@@ -1,5 +1,6 @@
-"""Mac specific module for conversion between pathnames and URLs.
-Do not import directly, use urllib instead."""
+"""Macintosh-specific module for conversion between pathnames and URLs.
+
+Do not import directly; use urllib instead."""
 
 import string
 import urllib
@@ -13,6 +14,11 @@
     tp = urllib.splittype(pathname)[0]
     if tp and tp <> 'file':
         raise RuntimeError, 'Cannot convert non-local URL to pathname'
+    # Turn starting /// into /, an empty hostname means current host
+    if pathname[:3] == '///':
+    	pathname = pathname[2:]
+    elif pathname[:2] == '//':
+        raise RuntimeError, 'Cannot convert non-local URL to pathname'
     components = string.split(pathname, '/')
     # Remove . and embedded ..
     i = 0