Are you having a problem locating where to press or are you not pressing hard enough?
You press the little rubber button with an indent at the bottom of the battery door. Press your nail into the indent hard enough and the door will pop right open for you.
Press that tab down, and the back will pop off. its not like other blackberry battery doors where you slide it off, you literally push the button and the door POPS off.
Now answer me this: what are those metal springs which surround the battery and connect to the metal battery door?