[ns] ns halting with no error information

[Julian Waldby <waldby@comm.csl.uiuc.edu>]

I am setting up a fairly large network, with about 400 links and 300 nodes in 
ns-2.1b7a. However, ns is halting at time 0 (or very close to that, since I have 
a report at time 0.1 that doesn't shows up), without informing me of what has 
caused it to halt. Is there a special run-mode that reports the cause of 
discontinuation? What is a good way to determine the problem?

Thanks,
Julian Waldby