diff --git a/Cabal/tests/PackageTests.hs b/Cabal/tests/PackageTests.hs
index 3ac9f6e2b9f8e409f2bddca4a5ba430b716442cb..3b45813093af1c15eff5ee56fc77dd286bf6edb5 100644
--- a/Cabal/tests/PackageTests.hs
+++ b/Cabal/tests/PackageTests.hs
@@ -210,6 +210,10 @@ getPersistBuildConfig_ filename = do
     eLBI <- try $ getConfigStateFile filename
     case eLBI of
       Left (ConfigStateFileBadVersion _ _ (Right lbi)) -> return lbi
-      Left (ConfigStateFileBadVersion _ _ (Left err)) -> throw err
+      Left (ConfigStateFileBadVersion _ _ (Left err))
+        -> error $ "We couldn't understand the build configuration.  Try " ++
+                   "building Cabal with a more recent version of itself " ++
+                   "and then running the test suite.\n\nOriginal error: " ++
+                   show err
       Left err -> throw err
       Right lbi -> return lbi