internal error: bad reference count


I am using bro 0.7a48 version on openBSD 2.9.
(I have made some changes to it.)

I am getting an internal error while running bro on a specific case.
Any pointers on when does an 'internal error' occur ?
If anyone one could give some pointers/ideas as to what might be the type
of error that would be helpful.

this is what gdb 'where' returned: