Flash :: Error 1136 : Incorrect Number Of Arguments. Expected 1

//Handle game logic
mcPlayer.update();
//create question
mcMathQu.update();

the first "update" function of external as file works , but the instance i added in the 2nd external file, it gives me that error... (there is a 3rd one behind it which works too)

note: the code itself is an external as file of a fla file. (and i checked, everything is linked properly to their individual external as file.

this is the whole function code. (still doing in process.)

public function update(evt:Event)
{
//This is the game loop
//Handle user input

[Code]...