I have edit this path inside my .bashrc file

export PATH=$PATH:/home/j0k3r/ns-allinone-2.35/bin:/home/j0k3r/ns-allinone-2.35/tcl8.5.10/unix:/home/j0k3r/ns-allinone-2.35/tk8.5.10/unix

export LD_LIBRARY_PATH=/home/j0k3r/ns-allinone-2.35/otcl-1.14, /home/j0k3r/ns-allinone-2.35/lib,