Do you see the bed temp in Pronterface when the "watch" box is checked? Even when not switched in it should show the room temp.
Also under "Settings" -> "Options" -> "user interface" check the "Display temperature gauges" box
Did you define the thermistor on the line:
#define TEMP_SENSOR_BED
Should be:
#define TEMP_SENSOR_BED 1
if there is a 100k thermistor
Is the #define MOTHERBOARD set at 33?
Steve