I got it to work by reading
If you've already done it before you have to pay or it will not work it says this maybe 1,000s of times
Try using a different internet connection and/or computer or pay the 4 euro.
I have to say though I hope I can find a way to get back to the original stock rom, I'm not liking this at all... :/ Hopefully getting rid of crappy sense, installing spb mobile shell, and doing some other stuff will make it actually usable. Can't find a way to get rid of the tactile feedback crap with the onscreen keyboard either, so gotta install another keyboard as well... The way sense handles messages really REALLY bites too. I think once I get rid of sense and get something that isn't so horrible I'll be happy with mighty rom.