MS (and probably other compiler vendors) are revising the string function to ensure greater safety. With strcpy, strcat and their variations, it's very easy to try to stuff more into a string array than it can hold. Therein lies the opening that many malware authors have exploited.
You can update your code to use the secure versions (they have an "_s" suffix and pass a parameter that is the size of the destination array), or continue with the old tried and true versions, adding the following to your code to suppress the warnings.
Use these #define's to halt the many warnings given by
Visual C++ 2005/2008 for use of "unsafe" string functions.
Place them before your #include statements.
see the link below for a full list of the functions that have
secure variations available