diff --git a/Spock.cabal b/Spock.cabal
--- a/Spock.cabal
+++ b/Spock.cabal
@@ -1,5 +1,5 @@
 name:                Spock
-version:             0.6.1.1
+version:             0.6.1.2
 synopsis:            Another Haskell web framework for rapid development
 description:         This toolbox provides everything you need to get a quick start into web hacking with haskell: routing, middleware, json, blaze, sessions, cookies, database helper, csrf-protection, global state
 Homepage:            https://github.com/agrafix/Spock
diff --git a/src/Web/Spock/Wire.hs b/src/Web/Spock/Wire.hs
--- a/src/Web/Spock/Wire.hs
+++ b/src/Web/Spock/Wire.hs
@@ -150,10 +150,9 @@
                     Just routeTree ->
                         case matchRoute' (Wai.pathInfo req) routeTree of
                           Just (captures, action) ->
-                              do (bodyParams, bodyFiles) <-
-                                     runResourceT $
-                                     withInternalState $ \st ->
-                                         P.parseRequestBody (P.tempFileBackEnd st) req
+                              runResourceT $
+                              withInternalState $ \st ->
+                              do (bodyParams, bodyFiles) <- P.parseRequestBody (P.tempFileBackEnd st) req
                                  let uploadedFiles =
                                          HM.fromList $
                                          map (\(k, fileInfo) ->
@@ -168,15 +167,15 @@
                                      queryParams = postParams ++ getParams
                                      env = RequestInfo req captures queryParams uploadedFiles
                                      resp = errorResponse status200 ""
-                                 (respState, _) <-
+                                 (respState, _) <- liftIO $
                                      (spockLift $ execRWST (runActionT action) env resp)
                                      `catch` \(e :: SomeException) ->
                                          do putStrLn $ "Spock Error: " ++ show e
                                             return (serverError, ())
                                  forM_ (HM.elems uploadedFiles) $ \uploadedFile ->
                                      do stillThere <- doesFileExist (uf_tempLocation uploadedFile)
-                                        when stillThere $ removeFile (uf_tempLocation uploadedFile)
-                                 respond $ respStateToResponse respState
+                                        when stillThere $ liftIO $ removeFile (uf_tempLocation uploadedFile)
+                                 liftIO $ respond $ respStateToResponse respState
                           Nothing ->
                               respond notFound
                     Nothing ->
@@ -235,7 +234,7 @@
            execRWST (runSpockT defs) (parentRoute `combineRoute` baseRoute) initState
        modify $ \st ->
            st
-           { ss_treeMap = HM.union (ss_treeMap st) (ss_treeMap finalState)
+           { ss_treeMap = HM.unionWith HM.union (ss_treeMap st) (ss_treeMap finalState)
            , ss_middleware = (ss_middleware finalState) . (ss_middleware st)
            }