Panic alarm on 2001 Toyota Sienna XLE mini-van

My panic alarm is going off every time I open my van with my key. I no longer have a remote opener. The dealer told me they could replace some parts (door mechanism, remotes, and then main computer) and cost us around $1000 but no guarantee it would help with the alarm. Is there any way to turn this off? Or are we doomed to leave our van unlocked?