What gives you an error message; the phone or the power supply?
If the power supply is behaving as if it were being shorted, then yes, you probably have a short on the PP_BATT_VCC or PP_VC_MAIN voltage rail on your logic board. You should do a very thorough visual inspection of the logic board, preferably with magnification (ideally, you will need to remove the shields). You may find some dislodged components or other signs of physical damage.
If that looks okay, then check the continuity of the main voltage rails (the schematics can be found...Google is your friend) and start your troubleshooting from there. Get back to us with your findings so we can guide you further.