zone 2 triggering alarm?

Hi ,newbie to this,recently installed a new veritas r8 ,replacing an old optima system[which had no problems other than old fashioned] i have used all the original wiring,pir and door contacts..however to get the system operational i have had to wire 3zones into zone 1 reason being,z1 was entry exit door,z2 dining room ,z3 front room ,z 4 front door,z 5 garage,i have to walk through the house to bed after setting the alarm. with the alarm in the timer /count down ,as soon as i step into z2 [dining room ] the alarm is immediate.What have i done wrong?help/advice will be grearfully acknowledged.