A question regarding a key script

[k.okkim]

Hey! I've been trying to script some stuff into my custom story (which is just something to make me learn c++ and the level editor) and I have a problem. I have a script which should allow me to use a key on a oor, unlock it and play a sound, but I keep getting this error message:

FATAL ERROR: Could not load script file
'custom_stories/ExampleStory/maps/00_example1.hps'!
main (3, 2) : ERR : No matching signatures to
'AddUserItemCallBack(string@&, string@&, string@&, string@&, const
bool)'

Here's the script: http://pastebin.com/4xp9mg8r

My key's name is single_use_master_key and the door name is level_wood_1.
I've also included the script file along with this post.

Does anyone know what's causing that, and how can I fix it? I've tried a lot of things, but the only thing I've managed to do was getting different and most likely more complicated error messages.

PS. Can I post my script here in a drop-down menu instead of using a pastebin link? If so, please tell me how.