>        The next stage is to work out what limit is the problem.
>        My guess would be stack or data - could you try them one by
>        one to identify which breaks it (assuming its only one :)


Your first guess was right. None of the others fixed the problem.
    diff ulimit.before ulimit.after
    < stack(kbytes)        512
    ---
    > stack(kbytes)        262144

The offending application appears to be Netscape Communicator 4.61
for Solaris 2.5.1 - running on Solaris 2.6 - under CDE with remote
Xserver on the NetBSD box.  But there are probably others ..

Now what ??

G.