Firefox breaks in upgrade from -BETA2 -> -BETA6

I updated from -BETA2 to -BETA6 (possibly -BETA3, don't remember) yesterday,
and firefox has broken.

When I start it, it just sits there, and doesn't open anything up.  The
process hangs in an unkillable state.  If I try to rebuild from scratch, the
package installation dies the same way while registering Chrome components
(regxpcom).  Even if I manually remove Firefox from my system, it still
fails while registering Chrome components.

Has anyone else seen this?  Might this have anything to do with the new
BIND (wild guess)?