Issue with Ethernet println..

Hi All,

Working on a project in which I need to make GR board to send values to a platform. For the same I am using Ethernet library.
 But there seems to be some problem with it. Following is the code:

/* GR-KAEDE Sketch Template V1.15 */
#include <Arduino.h>
#include <Ethernet.h>
#include <stdio.h>
#include "string.h"

String APIKEY = "765c66f66a91c85dec1d8c738a87efb288ebab5e50fc";
String DEVICE = "@uncleashi.uncleashiqazs";

// Enter a MAC address for your controller below.
// Newer Ethernet shields have a MAC address printed on a sticker on the shield
byte mac[] = {  0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };                //0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED
IPAddress ip(192,168,1,27);    
IPAddress server(82,223,244,60); 

EthernetClient client; // Initialize the library instance


// The setup routine runs once when you press reset
void setup() {

  Serial.begin(9600);             // Start serial port
  Serial.println(F("Starting"));

  Ethernet.begin(mac,ip);         // Start the Ethernet connection
  delay(1000);                    // Give the Ethernet shield a second to initialize
}

// The loop routine runs over and over again forever
void loop() {

  String txt = "";          // Text to send
     txt = "InComing!!!";

     
  Serial.println(txt);      // For debugging purpose only

  if (client.connect(server, 80)) {   // If there's a successful connection
    Serial.println(F("connected"));
    // Build the data field
    String json = "{\"protocol\":\"v2\",\"device\":\"@uncleashi.uncleashi\",\"at\":1356390000,\"data\":{\"light\":\""+txt+"\"}}";

    // Make a HTTP request
    client.println("POST /streams HTTP/1.1");
    client.println("Host: api.carriots.com");
    client.println("Accept: application/json");
    client.println("User-Agent: Arduino-Carriots");
    client.println("Content-Type: application/json");
    client.print("carriots.apikey: ");
    // client.println(APIKEY);
    client.println("765c66f66a91c85dec1d8c738a8cbe350eb6cc2122c8cb57efb288ebab5e50fc");
    client.print("Content-Length: ");
    int thisLength = json.length();
    client.println(thisLength);
    client.println("Connection: close");
   

client.println(json);

    
  }
  else {
    Serial.println(F("connection failed"));
  }


  if (!client.connected()) {
      client.stop();
  }
}

Following is the error which I am getting due to "client.println(json) and client.println(thisLength)":

The Compilation Is Complete

rx-elf-gcc -Wall -I"C:/Renesas/e2studio/GNURXv14.03-ELF/rx-elf/rx-elf/rx-elf/include" -I. -I"C:/Renesas/e2studio/GNURXv14.03-ELF/rx-elf/rx-elf/lib/gcc/rx-elf/4.8-GNURX_v14.03/include" -I"C:/Renesas/e2studio/GNURXv14.03-ELF/rx-elf/rx-elf/rx-elf/include/c++/4.8-GNURX_v14.03/" -I"C:/Renesas/e2studio/GNURXv14.03-ELF/rx-elf/rx-elf/rx-elf/include/c++/4.8-GNURX_v14.03/rx-elf/64-bit-double/" -ffunction-sections -fno-function-cse -fsigned-char -fdata-sections -mno-balign -DGRKAEDE -DGRSAKURA -DARDUINO=144 -DCPPAPP -D__RX_LITTLE_ENDIAN__=1 -D__T4__ -g2 -g -flto -mlittle-endian-data -m64bit-doubles -mcpu=rx64m -I./gr_build -I./gr_common -I./gr_common/core -I./gr_common/core/avr -I./gr_common/core/utility -I./gr_common/core/utility/driver -I./gr_common/core/utility/r_byteq_v1.30 -I./gr_common/core/utility/r_config -I./gr_common/core/utility/T4_src -I./gr_common/core/utility/T4_src/checksum -I./gr_common/core/utility/T4_src/checksum/rx -I./gr_common/lib -I./gr_common/lib/EEPROM -I./gr_common/lib/EEPROM/utility -I./gr_common/lib/Firmata -I./gr_common/lib/Image -I./gr_common/lib/Image/utility -I./gr_common/lib/LiquidCrystal -I./gr_common/lib/SD -I./gr_common/lib/SD/utility -I./gr_common/lib/Servo -I./gr_common/lib/SoftwareSerial -I./gr_common/lib/SPI -I./gr_common/lib/Stepper -I./gr_common/lib/Wire -I./gr_common/lib/Wire/utility -I./gr_common/rx64m -I./USB_Driver -c -x c++ gr_sketch.cpp -o gr_sketch.o
gr_sketch.cpp: In function 'void loop()':

client.println(thisLength);
^
In file included from gr_sketch.cpp:3:0:

size_t println(const char c[]){ /* get the length of the string * s return. '/ 0' is not included in length. */
^

client.println(json);
^
gr_sketch.cpp:57:24: note: candidates are:
In file included from gr_sketch.cpp:3:0:
./gr_common/core/Ethernet.h:256:16: note: size_t EthernetServer::println(const char*)
size_t println(const char c[]){ /* get the length of the string * s return. '/ 0' is not included in length. */
^
./gr_common/core/Ethernet.h:256:16: note: no known conversion for argument 1 from 'String' to 'const char*'
./gr_common/core/Ethernet.h:267:16: note: size_t EthernetServer::println()
size_t println(void){
^
./gr_common/core/Ethernet.h:267:16: note: candidate expects 0 arguments, 1 provided
make: *** [gr_sketch.o] Error 1

Any Help would be appreciated.
 Thanks in advance.