Firefox with "Spinlock" error

[Ned Harrison]

I keep getting this error when I try to start Firefox:  

Fatal error 'Spinlock called when not threaded.' at line 83 in 
file /usr/src/lib/libpthread/thread/thr_spinlock.c (errno = 0)
Abort trap (core dumped)

I read from a November post that this was related to out of date files in the 
~/.mozilla directory.  I could not find an answer from the mozilla web cite 
so I totally deleted that directory.  Still have the problem.  Any other 
suggestions?

Thank you in advance.