Might take a look at the RPi itself and see what it is getting from the sensor.
cd /sys/bus/w1/devices/
ls
cd 28-"put your serial here"
ls
cat w1_slave
if you get something that looks like this,
25 01 4b 46 7f ff 0b 10 65 : crc=65 YES
25 01 4b 46 7f ff 0b 10 65 t=18312
the last number, 18312 in my case, is the temp in milli-Celsius. So in my case it is 18.312°C in my back yard.
At least you will know if the sensor and RPi are working together.
My heartfelt thanks to pyromd76 over on http://faradaysclub.com/?p=907 for lernin’ me on this.
-Ian