Datacolor User to User Support Group.

The software I am using is Spyder2Pro 4.0.2. 

You are correct that I am calibrating in a dim room. I turned off the ambient light sensor, reset the target to 120 candelas and recalibrated with no change in the results...it again determined that the brightness of my monitor was in high 70s (78 this time) and reset the target. Although as Wim points out, the blue LED continues to flash during calibration even with that option turned off, so I wonder if it is still checking the ambient light.  

Interestingly enough, I am also using a Dell flat panel.