get_driver_instance() causes error LNK2005 (no replies)

I have followed the following tutorial: http://dev.mysql.com/doc/refman/5.1/en/connector-cpp-apps-windows-visual-studio.html

Now writing code expained in: http://blog.ulf-wendel.de/?p=215#hello

I get no errors on the includes or declaring the variables. However the line of code:
driver = get_driver_instance();
produces errors that say:
error LNK2005: "public: void __thiscall std::_Mutex::_Lock(void)" (?_Lock@_Mutex@std@@QAEXXZ) already defined in libcpmt.lib(xmutex.obj) C:\...\msvcprt.lib(MSVCP100.dll) MyProject

I have googled the error but i can't seem to find any useful explanation of what to do.