Edit: Fixed

 

where did you have your alarm installed at? best buy? (note to anyone out there do not let places like best buy or circuit city install anything, i've witnessed many horror stories. my bother had to take his supra into the dealer to get it rewired, best buy flipped the bill of course) anyways it sounds like the door trigger wire or the + - trigger is loose or possibly the ground. anyhow you should take it somewhere to have it fixed. I installed my own remote starter alarm on my wrx. good luck

 

sounds like the door triggers are not set up to the correct polarity
take it back to the idiot that installed it and tell them to get it right or take it out and give you your money back