Problem reading I2C

Other Hardware Robotics
3

the problem is de code below yes. E1 = pin 5 of pwm, E2 = pin 6 pwm en digital pin 7 en 4 are M1 and M2

		analogWrite(E1, 255);	//PWM Speed Control
		analogWrite(E2, 255);	//PWM Speed Control
		delay(30);
		digitalWrite(M1, HIGH);
		digitalWrite(M2, HIGH);

the SRF08 is connected to analog pin A5(SCL) en A4(SDA) of the arduino uno. It seems to be interfering because when i read the sensor without using above pwm code it works fine :~

MySonar is the class to read the srf08.