Car Alarms: Car Alarm Going Off, scion xb, alarmtek

Question
I have a 2004 Scion xB with a factory alarm in it. Recently for some reason, every time I hit the door open twice on my keyless entry remote (which hitting the door open twice will unlock all of the doors) the alarm goes off. It never happened before.. I even took out the space keyless entry remote to make sure the one I was using wasn't fried.. same thing happens? Do you have any idea how to fix this?

Answer
Please be more descriptive if possible.

"GOING OFF?"

I need to determine whether it's a factory alarm
issue or, if it's an aftermarket system you are
dealing with.

Is it: Headlights flashing, car horn honking
and a worded SECURITY" light in the dash flashing?
(doubtfull since none of the notes show this
car as having a factory alarm system)=FACTORY

Or,

is it: flashing parking lights,
an LED in the dash area, and a siren
going off?= AFTER MARKET

Let me know more on this to better
advise you on a course of action
to take.

Best Regards,

Robert Martin
CEO/ALARMTEK
CARALARMMAN.com