[ns] Error: CPP_NAMESPACE undeclared while installing NS-2.27

[Babu Raveendra]

Hello !

I am trying to install NS-2.27 in FreeBSD. When i am using normal configure, make i get the follwing error.
Any one for suggestions. 
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
In file included from ../../../config.h:54, 
from setdest.h:5, 
from setdest.cc:57:
 ../../../autoconf.h:85: error: namespace `CPP_NAMESPACE' undeclared 
setdest.cc:71:1: warning: "INFINITY" redefined 
In file included from /usr/include/math.h:40, 
from setdest.cc:43:
/usr/include/bits/mathdef.h:35:1: warning: this is the location of the previous definition make[1]: *** [setdest.o] Error 1 
----------------------------------------------------------------------------------------------------------------------------------
Regards
Raveendra