gm error

poraď te co mám spravit
var file, line, Addon_ditrectory;
Addon_ditrectory = filename_path("C:\RabigonCraft\Addons");

if !file_exists(Addon_ditrectory+"\Addon_list.txt") {
alarm[0]=1;
}
if file_exists(Addon_ditrectory+"\Addon_list.txt"){
if file_exists(Addon_ditrectory+"\Addon_list.txt"){
file = file_text_open_read(Addon_ditrectory+"\Addon_list. txt");
line_txt = file_text_read_string(file);
sprite = sprite_add(Addon_ditrectory/+line_txt,1,1,0,0,0);
sprite_index = sprite
file_text_close(file);
}
}
___________________________________________
ERROR in
action number 1
of Mouse Event for Left Pressed
for object obj_open_1:

Error in code at line 11:
sprite = sprite_add(Addon_ditrectory/+line_txt,1,1,0,0,0);
^
at position 54: Wrong type of arguments to unary operator.