Could someone explain why I am getting these errors:

Code:
#include <iostream>
#include <string>
#include <windows.h>
#include <cstdlib>
using namespace std;

int main()
{
	cout << "Hello world" << endl;
	system ("PAUSE");
	PlaySound("music30.wav.wav", NULL, SND_ASYNC | SND_FILENAME);
	system ("PAUSE");
	return 0;
}
------ Build started: Project: soundtest, Configuration: Debug Win32 ------
Compiling...
sound test.cpp
c:\documents and settings\hp_administrator\my documents\visual studio 2005\projects\soundtest\soundtest\sound test.cpp(11) : error C2664: 'PlaySoundW' : cannot convert parameter 1 from 'const char [16]' to 'LPCWSTR'
Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast
Build log was saved at "file://c:\Documents and Settings\HP_Administrator\My Documents\Visual Studio 2005\Projects\soundtest\soundtest\Debug\BuildLog.h tm"
soundtest - 1 error(s), 0 warning(s)
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

I AM NEW TO C++. Please explain in simple terms. Thank You