Thanks for giving it a look, I'll try and see whats up with it.

Same thing quits right after it opens,

10.5.6, imac

See my first comment; I believe it is working as designed, but there is no message to the user.

Sorry, yes - after registration, clicking on the icon will do nothing. It only does stuff if you drag-and-drop a file on the icon.

Please see this blog post for installation/usage help: http://blog.droplink.me/post/83016847/using-droplink