Are you using gcc or g++ to compile? For C++, you should be using g++.
Standard C++ headers don't use the .h extension. (e.g. <iostream>, <vector>, <string>, etc.) Standard C headers are pre-pended with a c and the .h is dropped. (e.g. <stdio.h> becomes <cstdio>) All other non-standard headers generally use the .h...
The new header names basically put everything into a namespace named std. So... you need to provide the full scope to the objects and functions within them, or use the "using namespace std;" line to inject those items into the global namespace. (Or use the using statment to inject only specific items from the namespace.)
Anyway, not sure if any of that is your problem or not, but it's some general guidelines that you can try. If you still can't get it to work, try posting more code, (Formatted between [code ] [ /code] tags, please...)