I'm just using the sketch that came with the DHT11.
The contents of that sketch seem to have slipped my mind, could you perhaps let us know more about it?
Just a row of boxes show on the LCD.
That's not good.
But I'm not trying to write the data to the LCD yet.
That's good, because you won't succeed until you deal with the boxes.
I am trying to figure out why I'm not getting data pulled up to the shield. Just as a test I did an lcd.print() of my variable and the LCD is displaying the same result as when I used Serial.println(). The sensor is just returning the value 0.00.
I don't understand this. You claim that you are not trying to write data to the LCD yet you mention using lcd.print.
How about making sure that your sketch is still running when the shield is attached. Insert some code to blink an LED each time it makes a measurement and see if the LED still blinks with the shield attached.
Don