malformed regular expression

[I've put back onto the cc line, since others may find
this dialog helpful]

I run it on FreeBSD4.2.
The run-time error appears some times, but not allways...
When I monitor an ethernet network, it may appear 10 times a day.
but yesterday I tried it on a gigabit link... and the error appears a lot

It seems to occur with some packet arrival.

$ bro -i wx0 mt.bro

The next thing to do is use -w tracefile to record the traffic that Bro is
reading, and then see if you can reproduce the problem using -r tracefile.
If so, send the trace to me and I'll track it down, and fix the error message.