problem with 02 Passat--locked out by ABS/EDL! Help!

I have an '02 Passat that won't let me start it; I turn the key, the
battery kicks in (radio and lights come on), but nothing happens after
that.

Here's the scenario:
Pulled into a parking space; shut the car off but left the key in the
ignition while I finished a phone call. About 2 minutes later, took the
key out and the ABS and Brake light on the dash start flashing,
accompanied by beeping. I double-checked that the car was in park, put
the key back in, tried to start it. No luck. Same thing after
repeated attempts to try inserting the key to see if that would clear
it out somehow. After a few tries, then the car icon with a key below
it (EDL according to the manual) also started flashing.

I had to give in and have it towed home; hubby will try disconnecting
the battery later to see if there's some kind of disconnect going on,
and I'll try the other key, but any thoughts or similar experiences?
What's going on? Is it related to the ABS, or is it that the car isn't
recognizing my key as valid? (The manual isn't super-clear and yes, I'm
a girl who isn't automotively clever.)

Thanks for any input. Not looking forward to having the dealer get a
few thousand from me to fix this if I can avoid it...if I can even get
it there, that is.