[ns] installation problem

[sparsh attre]

hi
i m facing a little problen in the installation of ns2.31 on fedora 5
it is installing properly but when i validate it thn it takes approx 45 -50
mins  and says that all tests have been passed
but whn i type ns on the command prompt it reflects an error saying
bash: ns command not found
can u get me out of this particulr problem?