Hi, Fion, I am getting the same error you got !! http://www-mash.cs.berkeley.edu/dist/archive/ns-users/9902/0078.html Any ideas on how to go around it ? I've installed (configure/make) ns-2.1b6 on HP-UX 10.20 platform running gcc-2.95.2/libstdc++-2.90.8. But I get coredumped on all tests. -- Martin