be explicit about the actual location of the missing file
diff --git a/Lib/distutils/dep_util.py b/Lib/distutils/dep_util.py
index c139c85..2c6d792 100644
--- a/Lib/distutils/dep_util.py
+++ b/Lib/distutils/dep_util.py
@@ -19,7 +19,8 @@
     Raise DistutilsFileError if 'source' does not exist.
     """
     if not os.path.exists(source):
-        raise DistutilsFileError, "file '%s' does not exist" % source
+        raise DistutilsFileError, ("file '%s' does not exist" %
+                                   os.path.abspath(source))
     if not os.path.exists(target):
         return 1