The docs I've found regarding that error seem to indicate it is an used caused by the 'using' directive. Are you calling 'using namespace std' or 'using std::list' either in the current file, or in an included header file?
Thanks a lot, I have removed 'using namespace std', but same error is occurring again. I have imported "ogresockets" and It seems like in it's header file there's a "using" directive calling . Do you have any idea to resolve the problem i have..?