Hi, i'm using boos libraries to add some extra functions in network simulator 2, ns-2, a network and protocols simulator, i have the version 2.34 working good with boost, but now i need to work with other version of ns2 the 2.27 version, i modified the Makefile as in the version i have already working, but i get the error below, but i really dont know what could be the reason of it. i'll aprecciate some help, or directions for fix it. Could be something related to the boost libraries were complied using gcc-4.3 and to compile this version of ns2 i need gcc-3.2.3???do i recompile boost libraries with gcc-3.2.3 version?? thanks /usr/bin/ld: warning: libstdc++.so.6, needed by /usr/local/lib/libboost_serialization.so, may conflict with libstdc++.so.5 /usr/lib/libstdc++.so.6: undefined reference to `_Unwind_Resume_or_Rethrow@GCC_3.3' /usr/lib/libstdc++.so.6: undefined reference to `_Unwind_GetIPInfo@GCC_4.2.0 ' collect2: ld returned 1 exit status make: *** [ns] Error 1 -- Pedro Alonso Chaparro Valero R&D Engineer Ciudad Politecnica de la Innovación iTEAM - Mobile Communications Group Polytechnic University of Valencia C\ Camino de Vera S/N, Edificio 8G 46022 Valencia, Spain