[ns] ns-2 installation problem

[moinul islam]

i am using cygwin 1.5.25 and ns-allinone-2.29.2 in windows vista.i have got the following problem:
 
Build Tk8.4.11
============================================================
configure: error: can not find sources in . or ..
tk8.3.2 configuration failed! Exiting ...
Tk is not part of the ns project.  Please see www.Scriptics.com
to see if they have a fix for your platform.