request )grappling hook

what does it mean when it says uknoun format and wont open?

Got the same problem over here :S the file has no extension, and no renaming wants to work.

I've done a bit of grappling hook work before, I find it quite easy to get the swinging motion going with a bit of trigonometry, it's getting the player's initial position set (where the player will be when he starts the swing, based on where he was standing before firing the hook) which is the complex part.

I reckon your best bet is Phizix, but it would take some work.