Backward migration fails on segmentation fault when using RC

I have been testing using RC2 by freezing this tag:

rake rails:freeze:edge TAG=rel_1-2-0_RC2

This morning, I tried to run a backward migration (-1 from current
version),
and Ruby barfed on a segmentation fault. Can anyone else see/try this?

$ rake migrate VERSION=13
(in /Users/lori/Projects/workspace/eTriever)
ruby(12541) malloc: *** Deallocation of a pointer not malloced:
0x1481038;
This could be a double free(), or free() called with the middle of an
allocated block; Try setting environment variable MallocHelp to see
tools to
help debug
ruby(12541) malloc: *** Deallocation of a pointer not malloced:
0x146f130;
This could be a double free(), or free() called with the middle of an
allocated block; Try setting environment variable MallocHelp to see
tools to
help debug
ruby(12541) malloc: *** Deallocation of a pointer not malloced:
0x10001;
This could be a double free(), or free() called with the middle of an
allocated block; Try setting environment variable MallocHelp to see
tools to
help debug
/Users/lori/Projects/workspace/eTriever/config/…/vendor/rails/activerecord/lib/…/…/activesupport/lib/active_support/dependencies.rb:322:
[BUG] Segmentation fault
ruby 1.8.4 (2005-12-24) [i686-darwin8.5.1]