"call compile" just doesn't like working with the default player variable. You have to assign a variable in editor. Don't ask me why but here is some example.
// Player without variable assigned in editor
_player1 = str player; _player1 = call compile _player1; _player1 // Returns Null
// Player with variable assinged in editor
_player1 = str player; _player1 = call compile _player1; _player1 // Returns Player