This problem has been around for quite some time. I first ran into this error over a year ago. No one found a solution, though -- it seems to be a rather obscure Javascript bug which only happens with Netscape under Linux (possibly other Unix platforms as well?). On Windows, neither Netscape nor IE exhibit this particular error. Also, Netscape only crashes if you submit two posts in a row with no intervening posts or login/out messages by others.
