Check this thread. You supercap may be dead or dying.

if you're adventurous, you could test it yourself with a multimeter. Here is a picture of the cap.

As Hugo said:

"check the voltage between the top of the cap and the bottom of it (the other pin is just visible on the other side of the cap). It should be around 3.5v-ish. If it's dead, it'll read <0.5v when the empeg is not powered."

BUT, do what Tony said and make sure it's not software.