Button errors popping up

I made a ROBOTC algorithm with this code:

#pragma config(Motor,  port1,           Climbmotor1,   tmotorVex393_HBridge, openLoop)
#pragma config(Motor,  port2,           Rmotor2,       tmotorServoContinuousRotation, openLoop)
#pragma config(Motor,  port3,           Climbmotor3,   tmotorServoContinuousRotation, openLoop)
#pragma config(Motor,  port4,           Larmmotor,     tmotorVex393_MC29, openLoop, reversed)
#pragma config(Motor,  port5,           Lmotor,        tmotorServoContinuousRotation, openLoop, reversed)
#pragma config(Motor,  port6,           Rmotor,        tmotorServoContinuousRotation, openLoop)
#pragma config(Motor,  port7,           Rarmmotor,     tmotorVex393_MC29, openLoop, reversed)
#pragma config(Motor,  port8,           Lmotor2,       tmotorServoContinuousRotation, openLoop, reversed)
#pragma config(Motor,  port9,           Clawmotor,     tmotorServoContinuousRotation, openLoop)
#pragma config(Motor,  port10,          Climbmotor2,   tmotorVex269_HBridge, openLoop)
//*!!Code automatically generated by 'ROBOTC' configuration wizard               !!*//

/*----------------------------------------------------------------------------------------------------*\
|*                           - Dual Joystick Control with Arm - 1 Remote -                            *|
|*                                      ROBOTC on VEX 2.0 Cortex                                      *|
|*                                                                                                    *|
|*  This program uses both the Left and the Right joysticks to run the robot using "tank control".    *|
|*  The Group 6 buttons on the top-right of the VEXnet Joystick are used to raise and lower an arm.   *|
|*                                                                                                    *|
|*                                        ROBOT CONFIGURATION                                         *|
|*    NOTES:                                                                                          *|
|*    1)  Ch1 is the X axis and Ch2 is the Y axis for the RIGHT joystick.                             *|
|*    2)  Ch3 is the Y axis and Ch4 is the X axis for the LEFT joystick.                              *|
|*                                                                                                    *|
|*    MOTORS & SENSORS:                                                                               *|
|*    *              [Name]              [Type]              [Description]                   *|
|*    Motor - Port 2          rightMotor           VEX Motor           Right motor                    *|
|*    Motor - Port 3          leftMotor            VEX Motor           Left motor                     *|
|*    Motor - Port 6          armMotor             VEX Motor           Arm motor                      *|
\*----------------------------------------------------------------------------------------------------*/

//+++++++++++++++++++++++++++++++++++++++++++++| MAIN |+++++++++++++++++++++++++++++++++++++++++++++++

//The value of the last button that was down. Is set to 0 initially because no button should be pressed at the beginning of the match.
int lastButtonValue = 0;
//Returns the current button being pressed. 0 if no button pressed.
int buttonValue() {
	if(vexRT[Btn8D] == 1) {
		return Btn8D;
	}
	else if(vexRT[Btn8R] == 1) {
		return Btn8R;
	}
	else if(vexRT[Btn6U] == 1) {
		return Btn6U;
	}
	else if(vexRT[Btn6D] == 1) {
		return Btn6D;
	}
	else if(vexRT[Btn5U] == 1) {
		return Btn5U;
	}
	else if(vexRT[Btn5D] == 1) {
		return Btn5D;
	}
	else if(vexRT[Btn7D] == 1) {
		return Btn7D;
	}
	else if(vexRT[Btn8U] == 1) {
		return Btn8U;
	}
	else if(vexRT[Btn8L] == 1) {
		return Btn8L;
	}
	else if(vexRT[Btn7U] == 1) {
		return Btn7U;
	}
	else {
		return 0;
	}
}
//Returns 1 if the last button you pressed is the specified button. Returns 0 if it isn't.
int didPressButton(int button) {
	//If the last button that was down is the specified button and no buttons are currently being pressed
	if (lastButtonValue == button && buttonValue() == 0) {
		return 1;
	}
	else {
		return 0;
	}
}

/**When the match starts**/
task main()
{
	//Forever
	while(true)
	{
		/**Driving controls**/
			//Forward button: 7U
			if(didPressButton(Btn7U)) {
				motor[Lmotor] = 127;
				motor[Rmotor] = 127;
			}
			//Backward button: 7D
			else if(didPressButton(Btn7D)) {
				motor[Lmotor] = -127;
				motor[Rmotor] = -127;
			}
			//Wheel brake: 8L
			else if(didPressButton(Btn8L)) {
				motor[Lmotor] = 0;
				motor[Rmotor] = 0;
			}

		/**Pivot controls**/
			//If the Left Joystick's Y axis is greater than 70
			if(vexRT[Ch4] > 70) {
				motor[Lmotor] = 127;
				motor[Rmotor] = -127;
			}
			//If the Left Joystick's Y axis is less than -70
			else if(vexRT[Ch4] < -70) {
				motor[Rmotor] = 127;
				motor[Lmotor] = -127;
			}

		/**Arm controls**/
			//Arm Up button: 6U
			if(didPressButton(Btn6U) == 1) {
				motor[Rarmmotor] = 127;
				motor[Larmmotor] = 127;
			}
			//Arm Down Button: 6D
			else if(didPressButton(Btn6D) == 1) {
				motor[Rarmmotor] = -75;
				motor[Larmmotor] = -75;
			}
			//Arm Brake: 8D
			else if(didPressButton(Btn8D) == 1) {
				motor[Rarmmotor] = 30;
				motor[Larmmotor] = 30;
			}

		/**Claw controls**/
			//Claw Up button: 5U
			if(didPressButton(Btn5U) == 1) {
				motor[Clawmotor] = 127;
			}
			//Claw Down Button: 5D
			else if(didPressButton(Btn5D) == 1) {
				motor[Clawmotor] = -127;
			}
			//Claw Brake: 8U
			else if(didPressButton(Btn8U) == 1) {
				motor[Clawmotor] = 20;
			}
			//Set the value of the last button that was down
			lastButtonValue = buttonValue();
	}
}
//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

(file attached)

And it didn’t have any errors when I initially compiled it, but upon opening it about the 10th time, errors showed up. The errors were talking about undefined variables, but those are the buttons I was using. It was working fine before, but now has errors. Even after compiling again, the errors stayed.
Log:

File “E:\2017.18 VEX\Software\Ptolemy’s 1st.c” compiled on Sep 25 2017 16:17:07
Error:Undefined variable ‘Btn8D’. ‘short’ assumed.
Error:Undefined variable ‘Btn8R’. ‘short’ assumed.
Error:Undefined variable ‘Btn6U’. ‘short’ assumed.
Error:Undefined variable ‘Btn6D’. ‘short’ assumed.
Error:Undefined variable ‘Btn5U’. ‘short’ assumed.
Error:Undefined variable ‘Btn5D’. ‘short’ assumed.
Error:Undefined variable ‘Btn7D’. ‘short’ assumed.
Error:Undefined variable ‘Btn8U’. ‘short’ assumed.
Error:Undefined variable ‘Btn8L’. ‘short’ assumed.
Error:Undefined variable ‘Btn7U’. ‘short’ assumed.
Error:Undefined variable ‘Ch4’. ‘short’ assumed.*

Make sure you didn’t accidentally change the platform to VexIQ.