diff --git a/Database/Persist/MongoDB.hs b/Database/Persist/MongoDB.hs
--- a/Database/Persist/MongoDB.hs
+++ b/Database/Persist/MongoDB.hs
@@ -134,6 +134,7 @@
 import Data.Conduit
 import Control.Monad.IO.Class (liftIO)
 import Data.Aeson (Value (Number), (.:), (.:?), (.!=), FromJSON(..), ToJSON(..), withText, withObject)
+import Data.Aeson.Types (modifyFailure)
 import Control.Monad (liftM, (>=>), forM_)
 import qualified Data.Pool as Pool
 import Data.Time (NominalDiffTime)
@@ -1118,7 +1119,8 @@
     deriving Show
 
 instance FromJSON MongoConf where
-    parseJSON = withObject "MongoConf" $ \o ->do
+    parseJSON v = modifyFailure ("Persistent: error loadomg MongoDB conf: " ++) $
+      flip (withObject "MongoConf") v $ \o ->do
         db                  <- o .:  "database"
         host                <- o .:? "host" .!= defaultHost
         NoOrphanPortID port <- o .:? "port" .!= NoOrphanPortID DB.defaultPort
@@ -1204,7 +1206,7 @@
   | forall nest. PersistEntity nest => EntityField record nest `LastNestFld` EntityField nest typ
   | forall nest. PersistEntity nest => EntityField record (Maybe nest) `LastNestFldNullable` EntityField nest typ
 
--- | A MongoRegex represetns a Regular expression.
+-- | A MongoRegex represents a Regular expression.
 -- It is a tuple of the expression and the options for the regular expression, respectively
 -- Options are listed here: <http://docs.mongodb.org/manual/reference/operator/query/regex/>
 -- If you use the same options you may want to define a helper such as @r t = (t, "ims")@
diff --git a/persistent-mongoDB.cabal b/persistent-mongoDB.cabal
--- a/persistent-mongoDB.cabal
+++ b/persistent-mongoDB.cabal
@@ -1,5 +1,5 @@
 name:            persistent-mongoDB
-version:         2.1.2.1
+version:         2.1.2.2
 license:         MIT
 license-file:    LICENSE
 author:          Greg Weber <greg@gregweber.info>
@@ -19,7 +19,7 @@
    Default: False
 
 library
-    build-depends:   base               >= 4 && < 5
+    build-depends:   base               >= 4.6 && < 5
                    , persistent         >= 2.1.1   && < 3
                    , text               >= 0.8
                    , transformers       >= 0.2.1
@@ -33,7 +33,7 @@
                    , cereal             >= 0.3.0.0
                    , path-pieces        >= 0.1
                    , monad-control      >= 0.3
-                   , aeson              >= 0.5
+                   , aeson              >= 0.6.2
                    , attoparsec
                    , time
                    , bytestring