when i install, it messages error: http://files.kde.org/necessitas/sdk/org.kde.necessitas.tools.qtcreator2.2.0.1qtcreator-windows.7z not found

Are you sure that was the URL?

It should be:

http://files.kde.org/necessitas/sdk/org.kde.necessitas.tools.qtcreator/2.2.0.1qtcreator-windows.7z

I tested it here and it worked, so if you did get the URL wrong then I think a network problem must have occurred. Did you try at a few different times? Are you behind a proxy?

If you can give me some reproduction steps then I'll investigate further.