Two things:

1) I doubt the dealership can say what is or is not a common problem, they know so little about these cars.
2) Don't call a dealership again and for CRYING OUT LOUD, don't let them near the car.


I'm with George - go get a cheap voltmeter at Radio Shack or Lowes; stick the probes on the battery terminals and make a note of the voltage reading, it should be 12.0 to 12.7 volts.

THEN turn the headlights on, note the voltage - you should see no more than .2 to .3 volt drop in what you see above. Note this voltage.

NOW, have a friend turn the key to start, and make a note of two things:
A) Note the voltage. (If it is under about 11.5 volts, the battery is just too weak)
B) Did the headlights dim briefly when the key was turned to start? If the battery voltage stays up around 12.5 volts, but the car still wont engage the starter AND the lights briefly dimmed, it's because the battery can't provide enough current and the drop in voltage that caused the lights to dim down confused the ECM and it is refusing to even try to engage the starter. It CAN be that you have such corroded/dirty battery terminals that the battery is actually ok, but not enough current can flow to run the starter. By turning lights on, you can "see" the voltage dip and recover easier than with the meter.

Let us know what you find.