IDE not accepting the LiquidCrystal library (I think)

So, I wanted to make a stroboscope with a 16x2 display. I'm using the mighty LiquidCrystal library.

30 minutes before it worked fine, but now I get the error message:

Mehrere Bibliotheken wurden für "LiquidCrystal.h" gefunden
 Benutzt: C:\Program
exit status 1
'rs' was not declared in this scope

And don't wonder, the first row is german and means: 'More than one library was found for "LiquidCrystal.h"
Used: C:Programs(x86)'

Also, here is the code:

#include <LiquidCrystal.h>

LiquidCrystal lcd(rs, en, d4, d5, d6, d7);
const int rs = 12, en = 11, d4 = 5, d5 = 4, d6 = 3, d7 = 2;

int period = 500 ;
unsigned long time_now = 0;

/*
 * Frequency and Duty controlable Stroboscope - LCD Feedback
 *
 * Gamesnic
 */
 
#define mosfet  13                                   //MOSFET gate on digital pin 13
#define pot     A0                                  //wiper from potentiometer on analog pin 0
#define pot1     A1
int wait = 0;                                       //delay times for Duty and Frequency
int wait1 = 1;
 
void setup() {
 
  pinMode(13,OUTPUT);                                //digital pin 13 set for output
  pinMode(A0,INPUT);                                //analog pin 0 set for input
  pinMode(A1,INPUT);                                //analog pin 1 set for input
  Serial.begin(250000);                             //begin serial communication
  lcd.begin(16, 2);                                 //begin LCD
  lcd.setCursor(2, 0);
  lcd.write("Initializing"), lcd.setCursor(4, 1), lcd.write("system        ");
  delay(333);
  lcd.write("Initializing"), lcd.setCursor(4, 1), lcd.write("system.       ");
  delay(333);
  lcd.write("Initializing"), lcd.setCursor(4, 1), lcd.write("system..       ");
  delay(333);
  lcd.write("Initializing"), lcd.setCursor(4, 1), lcd.write("system...       ");
  delay(333);
  lcd.write("Initializing"), lcd.setCursor(4, 1), lcd.write("system        ");
  delay(333);
  lcd.write("Initializing"), lcd.setCursor(4, 1), lcd.write("system.       ");
  delay(333);
  lcd.write("Initializing"), lcd.setCursor(4, 1), lcd.write("system..       ");
  delay(333);
  lcd.write("Initializing"), lcd.setCursor(4, 1), lcd.write("system...       ");
  delay(333);
  lcd.write("Loading"), lcd.setCursor(3, 1), lcd.write("Oscillator.        ");
  delay(333);
  lcd.write("Loading"), lcd.setCursor(3, 1), lcd.write("Oscillator..       ");
  delay(333);
  lcd.write("Loading"), lcd.setCursor(1, 1), lcd.write("MOSFET system...         ");
  delay(667);
  lcd.write("Loading"), lcd.setCursor(2, 1), lcd.write("Serial Debug          ");
  delay(333);
  lcd.write("Loading"), lcd.setCursor(2, 1), lcd.write("Serial Debug.        ");
  delay(333);
  lcd.write("Loading"), lcd.setCursor(2, 1), lcd.write("Serial Debug..        ");
  delay(50);
  lcd.write("Loading"), lcd.setCursor(1, 1), lcd.write("PWM Modulator...             ");
  delay(283);
  lcd.write("Loading"), lcd.setCursor(1, 1), lcd.write("PWM Modulator              ");
  delay(333);
  lcd.clear();
  lcd.setCursor(4, 0), lcd.write("Loading                "), lcd.setCursor(3, 1), lcd.write("complete!              ");
  delay(1200);
  lcd.clear();
  delay(1000);
  lcd.setCursor(2, 1), lcd.write("Starting OS         ");
  delay(1500);
  lcd.clear();
}
 
void loop() {
int pRead = analogRead(pot);                      //begin each loop by reading the position of the pot
int pRead1 = analogRead(pot1);
wait = map(pRead,0,1000,1,200);                //map the analog read to a value between 1mS to 200ms
wait1 = map(pRead1,0,1000,1,200);             
  if(millis() > time_now + period){             //make the display only refresh every 500ms
        time_now = millis();
         
    }
  lcd.setCursor(0, 0);
  lcd.write("Freq: "), lcd.setCursor(7, 0), lcd.write(wait), lcd.setCursor(12, 0), lcd.write("ms  ");
  lcd.setCursor(0, 1);
  lcd.write("Duty: "), lcd.setCursor(7, 1), lcd.write(wait1), lcd.setCursor(12, 1), lcd.write("ms  ");
digitalWrite(mosfet,HIGH);                        //flash the MOSFET
delay(wait1);                                       //wait for the Frequency time
digitalWrite(mosfet,LOW);                         //shut off the MOSFET
delay(wait);                                      //wait for the Duty time
  }

Also all of that lcd. stuff in void setup is just for fanciness, has nothing to do with the code.

(deleted)

Oh frick, thanks! You saved me!
Oh lord spycatcher2k, thanks for making my code usable just by changing a simple piece of it.
Amen