anyone remember fixing this bug (in serial debugger in 6.1)

I've been hitting a bug in 6.1.

In the serial debugger, after typing a few commands
it stops listening to the serial input.  I can pund on hte keyboard as 
much as I want but it is no longer listening.. power cycle is he only 
answer.. I have sent an NMI.. it brings a new ddb prompt, but it is 
still not listening to the serial input (but it shows the serial output 
is fine).

Does this sond familiar to any one.
Dell 2950 in 32 bit mode if it makes any difference.


Julian.