Every function not declared all of the sudden

I realized I forgot to give one of my functions LCDPrint a data type of ‘int’ for my variables. as soon as I did that is stopped recognzing EVERY single function in the script. Can anyone tell me how this happened

#include <Bounce.h> 


#define debug
#define maxMenus 20
#define upButton  13
#define enterButton  12
#define downButton  11
#define motorOutFwd  9
#define motorOutbwd  10

#define C2Switch  7
#define C3Switch  6
#define motorInFwd  5
#define motorInBwk  4
#define motorAdjOne  3
#define motorAdjTwo  2


Bounce bouncerUp = Bounce( upButton, 10); 
Bounce bouncerEnter = Bounce( enterButton, 10); 
Bounce bouncerDown = Bounce( downButton, 10); 



void setup() {

  
  pinMode(upButton, INPUT); 
  pinMode(enterButton, INPUT); 
  pinMode(downButton, INPUT); 
  
  
  Serial.begin(9600);
  backlightOn();
}

void loop() {
  int menuScreen = 0; // Setup Menu Screen
  
  //update the debouncer
  bouncerUp.update ( );
  bouncerEnter.update ( );
  bouncerDown.update ( );
   
  //Get value of buttons
  int valueUp = bouncerUp.read();
  int valueEnter = bouncerEnter.read();
  int valueDown = bouncerDown.read();
 
 
 //get default value assigned to menuScreen
  if(menuScreen == 0){
    menuScreen = 1;
  }
  else{
    menuScreen = menuScreen;
    }
    
    
    if(valueUp == HIGH){
      if (menuScreen > maxMenus){
        menuScreen = 1;
        LCDPrint(menuScreen);
      }
      else{
        menuScreen++;
      }
    }// End up if statement
    if(valueDown == HIGH){
      if(menuScreen == 0){
        menuScreen = (maxMenus -1);
      }
      else{
        menuScreen --;
      }
    }//end if
      
      
    }   
    

void LCDPrint(int menuScreen){
  switch (menuScreen){
    case 1:  
      selectLineOne();
      Serial.println("one");
      break;
    case 2:  
      selectLineOne();
      Serial.println("two");
      break;
    case 3:  
      selectLineOne();
      Serial.println("three");
      break;
    case 4:  
      selectLineOne();
      Serial.println("four");
      break;
    case 5:  
      selectLineOne();
      Serial.println("five");
      break;
    case 6:  
      selectLineOne();
      Serial.println("six");
      break;
    case 7:  
      selectLineOne();
      Serial.println("seven");
      break;
    case 8:  
      selectLineOne();
      Serial.println("eight");
      break;
    case 9:  
      selectLineOne();
      Serial.println("nine");
      break;
    case 10:  
      selectLineOne();
      Serial.println("ten");
      break;
    case 11:  
      selectLineOne();
      Serial.println("eleven");
      break;
    case 12:  
      selectLineOne();
      Serial.println("twelve");
      break;
    case 13:  
      selectLineOne();
      Serial.println("thirteen");
      break;
    case 14:  
      selectLineOne();
      Serial.println("fourteen");
      break;
    case 15:  
      selectLineOne();
      Serial.println("fifteen");
      break;
    case 16:  
      selectLineOne();
      Serial.println("sixteen");
      break;
    case 17:  
      selectLineOne();
      Serial.println("seventeen");
      break;
    case 18:  
      selectLineOne();
      Serial.println("eighteenteen");
      break;
    case 19:  
      selectLineOne();
      Serial.println("nineteen");
      break;
    case 20:  
      selectLineOne();
      Serial.println("twenty");
      break;
    default:
      break;
  }// end case   
      
     
    
    
  
}//end LCD function


void MotorOutput(){
}


void selectLineOne(){  //puts the cursor at line 0 char 0.
   Serial.write(0xFE);   //command flag
   Serial.write(128);    //position
   delay(10);
}
void selectLineTwo(){  //puts the cursor at line 0 char 0.
   Serial.write(0xFE);   //command flag
   Serial.write(192);    //position
   delay(10);
}

void goTo(int position) { //position = line 1: 0-15, line 2: 16-31, 31+ defaults back to 0
if (position<16){ Serial.write(0xFE);   //command flag
              Serial.write((position+128));    //position
}else if (position<32){Serial.write(0xFE);   //command flag
              Serial.write((position+48+128));    //position 
} else { goTo(0); }
   delay(10);
}

void clearLCD(){
   Serial.write(0xFE);   //command flag
   Serial.write(0x01);   //clear command.
   delay(10);
}
void backlightOn(){  //turns on the backlight
    Serial.write(0x7C);   //command flag for backlight stuff
    Serial.write(157);    //light level.
   delay(10);
}
void backlightOff(){  //turns off the backlight
    Serial.write(0x7C);   //command flag for backlight stuff
    Serial.write(128);     //light level for off.
   delay(10);
}
void serCommand(){   //a general function to call the command flag for issuing all other commands   
  Serial.write(0xFE);
}

The examples in the bounce library cause errors as well.....

When I try your code I get:-

/Applications/Arduino.app/Contents/Resources/Java/libraries/Bounce/Bounce.cpp:4:22: error: WProgram.h: No such file or directory

That means the bounce library is not compatible with Arduino IDE 1.0 and above.
You need to change that include.
See the how to use this forum stick for the cure.