'serial' was not declared in this scope error HELP!!!

at this point i feel like i've tried it all, and hopefully its just something I'm missing. I'm trying to load a code onto an arduino mega 2650 with an xbee shield and 9dof imu connected to it…. PLEASE HELP ME OUT!
thank you !!

#include<Arduino.h>

void setup() {
// initialize both serial ports:
Serial.begin(57600);
Serial1.begin(57600);
}

void loop() {
// read from port 1, send to port 0:
while (Serial1.available()) {
char inByte = Serial1.read();
Serial.write(inByte);
}
}

Code i've been running…

and the error I can't get past ….

transmittt.ino: In function 'void setup()':
transmittt:5: error: 'Serial' was not declared in this scope
transmittt:6: error: 'Serial1' was not declared in this scope
transmittt.ino: In function 'void loop()':
transmittt:11: error: 'Serial1' was not declared in this scope
transmittt:13: error: 'Serial' was not declared in this scope

i've tried a lot of the suggestions out there but maybe I'm just too new at this to dig myself out of this hole!!

thanks

That code compiles fine on my computer.
Have you set the board type in the Tools menu to Mega 2560 ?

I've never needed the line

#include<Arduino.h>

But it still compiles for me with or without.

You might want to consider re-installing the ide, perhaps the path setting have been corrupted?

PHEW that sounds easy! i will give both of these a try, all though I'm pretty sure I've got my board right but I could be wrong! I will update my progress.
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