Help, van won't start !

We bought a '97 Venture about two weeks ago. Today my wife had the van and after unlocking the passenger side sliding door set off the theftlock system. Of course, now it won't start.

She tried the reset procedure several times, switch to ACC, wait for the light to go off, but this doesn't work. Everything I find has to do with the ignition switch, but the alarm was set by the side door. What can we do to get the van going?