diff --git a/schedevr.cabal b/schedevr.cabal
--- a/schedevr.cabal
+++ b/schedevr.cabal
@@ -2,7 +2,7 @@
 -- documentation, see http://haskell.org/cabal/users-guide/
 
 name:                schedevr
-version:             0.1.0.1
+version:             0.1.0.2
 synopsis:            Marge schedules and show EVR
 -- description:         
 license:             BSD3
diff --git a/src/mkschd/Output.hs b/src/mkschd/Output.hs
--- a/src/mkschd/Output.hs
+++ b/src/mkschd/Output.hs
@@ -54,7 +54,8 @@
 fromItemN _ [] = []
 fromItemN d ias
 	| any null ias = fromItemN d $ filter (not . null) ias
-	| any (flip isLate d) (map head ias) = error "too late"
+	| any (flip isLate d) (map head ias) = error $ "too late: " ++
+		show (head $ filter (flip isLate d) (map head ias))
 fromItemN d ias = fromItemNSelect [] d es diag ias
 	where
 	es = map (flip ending d . head) ias