--- a/Plugins/VcsPlugins/vcsMercurial/HgDiffDialog.py	Fri Sep 16 18:55:43 2011 +0200
+++ b/Plugins/VcsPlugins/vcsMercurial/HgDiffDialog.py	Fri Sep 16 18:56:43 2011 +0200
@@ -154,15 +154,14 @@
             
             out, err = self.__hgClient.runcommand(args)
             
+            if err:
+                self.__showError(err)
             if out:
                 for line in out.splitlines(True):
                     self.__processOutputLine(line)
                     if self.__hgClient.wasCanceled():
                         break
             
-            if err:
-                self.__showError(err)
-            
             self.__finish()
         else:
             # find the root of the repo