Fix more exception slicing.
diff --git a/Lib/distutils/file_util.py b/Lib/distutils/file_util.py
index e29e90e..6919060 100644
--- a/Lib/distutils/file_util.py
+++ b/Lib/distutils/file_util.py
@@ -139,7 +139,7 @@
             macostools.copy(src, dst, 0, preserve_times)
         except os.error as exc:
             raise DistutilsFileError(
-                  "could not copy '%s' to '%s': %s" % (src, dst, exc[-1]))
+                  "could not copy '%s' to '%s': %s" % (src, dst, exc.args[-1]))
 
     # If linking (hard or symbolic), use the appropriate system call
     # (Unix only, of course, but that's the caller's responsibility)