Shoutbox

Another question : I want to have different effects based on the contact i send messages to. I made a function to replace the message to avoid being redundant

here's the code i use :
var MsgOutput = null;
var Color1 = null;
var Color2 = null;
function Replace_Text(Color1, Color2, Message, MsgOutput)
{
    MsgOutput = "[c=" + Color1 + "]" + Message + "[/c=" + Color2 + "]";
}
function OnEvent_ChatWndSendMessage(ChatWnd, Message)
{
    if (Contact.Email == xxxxx@xxxxxxx) {
        Color1 = "#010176";
        Color2 = "#2D0352";
        Replace_Text(Color1, Color2, Message, MsgOutput);
    }
    return MsgOutput;
}

But i can't start the script, i get an error. Has anybody ideas why?