Error: Unexpected token {

[ModManDann]

void OnEnter();
{
AddEntityCollideCallback("Player" , "ScriptArea_3" , true , 1);
}

remove the ; from void onEnter(), when you create a function you NEVER put ; behind that. This is also the case for if statements, for loops etc.

It should look like:

void OnEnter()
{
AddEntityCollideCallback("Player" , "ScriptArea_3" , true , 1);
}