I also had trouble initially with my dock. It turned out that the (-) contacts within the Pronto battery compartment were not pressing firmly enough against the battery pack. If you too are having trouble with the battery, you may want to check the contacts.

The Pronto would appear to have no power until I pressed down on the bottom of the battery - then the lights on the hard buttons would flicker but the unit would not stay on.

I examined the battery/battery compartment and noticed that the outer two bottom contacts supply negative(-). I took a small pin and used it to pry these two contacts so that they protruded slightly more. Put the battery back in and voila! Now it works perfectly. One note of caution - be careful that you do not exert too much force bending the contact or it may snap off.