Hi,
Maybe you have tried this. But fwiw.
I have had the same problem with some apps. I tried the redownload, sometimes more than one time, and in the end i got a download. So try redownload button, if you have'nt done that yet.
I had a very slow net connection the day i downloaded. Maybe that had something to do with the download error too, as a bad net connection can give timeout errors and other errors if the connection fail at a point.
But also it's very possible the error is on Arturis's side. So Arturia should take a look at that. Anyway you can try redownload and check your net connection. If that's not helping, Arturia have to solve the problem.