[Konstantinos]

You declare a variable as integer and in a public function, you're trying to set a text for it even if it's not an array.

pawn Код:

new ServerArea = 1;
new ServerAreaName[20];

public ChangeMode()
{
    switch(ServerArea)
    {
        case 1: ServerAreaName = "Deathmatch";
    }
    return 1;
}