Now I found out the problem. The problem was due to the not linking c++ in old version of gcc, as I installed older version of gcc.
Oh, god!! finally I found out the problem. I searched 2 days for the solution on the net.
cc: In member function ‘void std::vector<_tp,>::_M_range_insert(__gnu_cxx::__normal_iterator
/usr/lib/gcc/i386-redhat-linux/4.1.2/../../../../include/c++/4.1.2/bits/vector.tcc:452: error: expected unqualified-id before ‘(’ token
make: *** [diffusion3/ns/difftimer.o] Error 1
Ns make failed!