[ns] install problem

[Kai Li <kli@uncc.edu>]

I installed ns-allinone-2.1b7a in my directory. Now I download the cmu wireless
extension under ns-allinone-2.1b7a, then I unpack the cmu file and it creates 
the ns-src, now something like :

/ns-allinone-2.1b7a/ns-2.1b7a
/ns-allinone-2.1b7a/ns-src

now I go to ns-src and try to run:
sh configure
but it gives me the following error:
configure: error: tcl is required but could not be completely found.

Can sb. help me to solve such problem? Thanks a lot..

KL