Welcome to LQ.
Some (all) information is missing in post #1.
OS Name and version.
OS architecture : i686 or x86_64 ?
The name of the awk script.
Any changes, patches added to ns2 ?
The simulation command, like $ ns file-name.tcl
The file that you are trying to process with awk.
→ Large files(.tr) can be uploaded to Google Docs,