Hmm that's an interesting theory, but I've never been able to send messages on people's walls, been like that since I created an account. Like the original post said, the button goes green when I press it, but doesn't do anything and goes grey when I move my cursor. Thank you for the help though, I'll contact customer service later : )
(Really sorry but can you explain how to contact customer service? I can't find an option anywhere on tapas lol)