I get the same message!

I've been getting it all day also. It was doing it at least 10 hours ago, and I am still getting the same message when attempting an upload of the collection.

I guess it's just the "working on the servers" that's doing it then.

I was getting the same problem last night when trying to upload . I eventually managed to contribute 1 title   but have yet to successfully upload my collection , but I guess that it was during that period while the system was unavailable .
I understand about downtime and as I work in the IT industry appreciate that new releases can be problematic, but I think that the new version is great   and look forward to the time when all is well.
I am at work at present, so will try my upload again later this evening.