homepage: wrong url or not found - created iWeb 2

Hi,
again and again I got problems with mobileMe an homepage access.
Having built a new page with iWeb 2.0 or altered something, the new page will open or not not. In the last case an error will be produced:
"Sorry but we can't find the iWeb page you've requested. It's possible that:
· The address was entered incorrectly. Check your spelling and try again.
· The .Mac member of this name has either created a page and removed it or has never published an iWeb site.
· There is no .Mac member of this name. If you'd like this member name for yourself, sign up for a .Mac account right now and have your own iWeb site in minutes."
I had several chats with mobileMe-Service. Result: the problem seemed to be solved, but then appeared again!
Any idea?
Thanks!
Charly