Hi: I just got everything (tcl/tk, otcl, tclcl, ns, perl) compiled with no errors. Then I tried starting ns, there was the error: ns: tcl error on eval of: $a set size_ [AllocAddrBits set MAXADDRSIZE_] Followed by dumping many many lines of tcl scripts, something like from ns/gen/ns_tcl.cc. Any help will be appreciated. Philip