Batch mutate doesn't work

[Zubair Quraishi]

I have the following code in Erlang to set a value and then add a
property. The first set works but the mutate fails. Can anyone
enlighten me?
Thanks

 {ok, C} = thrift_client:start_link("127.0.0.1",9160, cassandra_thrift),

 Key = "Key1",

 %
 % set first property
 %
 thrift_client:call( C,
                  'insert',
                  [ "Keyspace1",
                    Key,
                    #columnPath{column_family="KeyValue", column="value"},
                    "value1",
                    1,
                    1
                    ] ),

 %
 % set second property ( fails! - why? )
 %
 MutationMap =
 {
   Key,
   {
     <<"KeyValue">>,
     [
       #mutation{
         column_or_supercolumn = #column{ name = "property" , value =
"value" , timestamp = 2 }
       }
     ]
   }
 },
 thrift_client:call( C,
   'batch_mutate',
   [ "Keyspace1",
      MutationMap,
      1
   ] )

: The error returned is :

** exception exit: {bad_return_value,{error,{function_clause,[{dict,size,
                                                                   [{"Key1",

{<<"KeyValue">>,

[{mutation,{column,"property","value",2},undefined}]}}]},

{thrift_protocol,write,2},

{thrift_protocol,struct_write_loop,3},

{thrift_protocol,write,2},

{thrift_client,send_function_call,3},

{thrift_client,'-handle_call/3-fun-0-',3},

{thrift_client,catch_function_exceptions,2},

{thrift_client,handle_call,3}]}}}
7>
=ERROR REPORT==== 30-Apr-2010::15:13:42 ===
** Generic server <0.55.0> terminating
** Last message in was {call,batch_mutate,
                          ["Keyspace1",
                           {"Key1",
                            {<<"KeyValue">>,
                             [{mutation,
                                  {column,"property","value",2},
                                  undefined}]}},
                           1]}
** When Server state == {state,cassandra_thrift,
                        {protocol,thrift_binary_protocol,
                         {binary_protocol,
                          {transport,thrift_buffered_transport,<0.58.0>},
                          true,true}},
                        0}
** Reason for termination ==
** {bad_return_value,
      {error,
          {function_clause,
              [{dict,size,
                   [{"Key1",
                     {<<"KeyValue">>,
                      [{mutation,
                           {column,"property","value",2},
                           undefined}]}}]},
               {thrift_protocol,write,2},
               {thrift_protocol,struct_write_loop,3},
               {thrift_protocol,write,2},
               {thrift_client,send_function_call,3},
               {thrift_client,'-handle_call/3-fun-0-',3},
               {thrift_client,catch_function_exceptions,2},
               {thrift_client,handle_call,3}]}}}