Really dumb question from g++ newbie

I've developed my library with MSVC7 and am now trying to test on as many compiler as possible. Using g++ 2.95.3-5 on cywin, I get a compiler error using std::distance `distance' undeclared in namespace `std' I have tried all the obvious includes, but the problem seems to be a configuration issue for using namespaces. The code compiles on VC7/Dinkumware, VC7/STLport-4.5.3 and BCC 5.5.1 so I am confident that there is no error in the code itself. Could someone please point me in the right direction? TIA -- Craig