For future reference, I did have a backup link in the ReadMe which still works courtesy of Slayne. That would be this:
http://www.digitalsloth.net/ys/YS2OP_1.AVIAnyhow, I am aware of this problem and it'll be taken care of with the next update of the Ys II patch. I will use the above link and maybe ask Gillian if the patcher can randomly choose between that link or the one from his site, assuming he expects his server to be around for a long time. Unfortunately, in the meantime, everybody who is running the current patch is having the old AVI simply being erased and set to size 0...