Since you' re mentioning the .deb-file, i assume you installed ns via Software-Center.
Please try installing ns2 following these instructions: http://askubuntu.com/questions/467901/segmentation-fault-core-dumped-in-ns2-ubuntu-14-04 The tcl-file you posted in the other thread calls nam. So as long as nam won't run by itself, the error you get with the tcl-script seems to be clear ...
