I've been clicking on the same dance link on the past hour, everything went fine, now it tells me error, invalid link?! No one changed it @ how come it's suddenly invalid?!

Because the link expires every so often. This is intentional and normal.

?!?! Why?! To make it just a bit dificult, because everything else goes soooo fine and dandy?! eyeroll Thanks for answering :)

They change the link to stop people from using auto-refreshers. But anyway locking since it is not a bug.