[BigETI]

pawn Код:

#if defined FILTERSCRIPT

public OnFilterScriptInit()
{
    print("\n--------------------------------------");
    print(" Radio System is starting ..");
    print(" Radio system has started.");
    print("--------------------------------------\n");
    return 1;
}

public OnFilterScriptExit()
{
    print("\n--------------------------------------");
    print(" Radio System has been shut down due to a Filterscript unload/Exit.");
    print("--------------------------------------\n");
    return 1;
}

#else

main()
{
    print("\n----------------------------------");
    print(" Radio Tutorial by PlayHard. Powered by PlayHard's Tutorials :P");
    print("----------------------------------\n");
}

#endif

In this part you know that OnFilterScriptInit() and OnFilterScriptExit() gets never called since the compiler won't compile the lines.
And main() does not get called for a filterscript.

remove the part with "#if defined FILTERSCRIPT", "#else" and "#endif".