This is an old subject, but I thought I would post how I solved the problem.
Evidently, when I was working under the dash at some point, I managed to hit the small L-shaped bracket thru which the parking brake release rod goes (probably, with my head). I managed to bend one leg of the bracket enough so that it exerted just a little tension on the back side of the release handle. Just enough tension, it turns out, to prevent the brake from engaging.
Straightened the bracket, so that 1/4" of play remained between the bracket and the handle (like the manual says), and all good now.
