Many aftermarket alarm systems also disable engine starting. If the problem started after installing the alarm, you may want to try disconnecting the alarm system to see if the engine will then start.
If it is not related to the alarm system, then you should call the Dodge dealer and have them tow your car in for repair. This is a brand new 2008 model and is under factory warranty. Any attempt you might make to disassemble the vehicle or repair the problem may void your warranty and result in you having to pay for warranty repairs that should be free.