I went to start the ES350 and the steering wheel was locked. I kept pushing the start button and wiggling the wheel and eventually the engine started and the wheel became unlocked. What happened?

 

An electrical signal initiated by pressing the Start Button, unlocked it. Perfectly normal. Equivalent to turning the ignition key to unlock the manual steering lock.

 

Seen this more frequently in the winter time, if you brace yourself when exiting the
car by holding the steering wheel and it rotates a bit sometimes the steering wheel
lock mechanism Tootsall referred to will catch. When the electric lock is fighting
the torque of the column and can not release you get the error message.
As with the older key operation, turn the wheel to relieve the load on the lock
and away you go.

 

Very good explanation. Couldn't have stated it more clearly myself...