Need Help with credits.

[A Tricky Carnie]

Ok, so I set my credits to its own map and have it so the player will spawn on an area and it will start the credits, anyway here is my script for it:

Spoiler below!

////////////////////////////// Run when entering map
void OnStart()
//OnEnter
{
AddEntityCollideCallback("Player", "ending_area", "StartCredits", true, 1);
}
void StartCredits(string& asMusic, bool abLoopMusic, string& asTextCat, string& asTextEntry, int alEndNum)
{
StartCredits("05_paper_transformation.ogg", true, "Ending", "MainCredits", "1");
}

// Run when leaving map
void OnLeave()
{

}

also, the error message I'm receiving when the game crashes is this:

Spoiler below!

main (7,1) : ERR : A function with the same name and parameters already exist
main (9,2) :ERR: No matching signatures to 'StartCredits(string@&, constbool, string@&, string@&, string@&)'

If you need anymore information, just tell me, and thanks for any help in advance.