Hello Manto,
These seem like DotNetNuke issues and not direct issues with any of our Products. I would recommend looking through the DNN Forums at
http://www.dotnetnuke.com/Resources/Forums.aspx Usually when upgrading from such a legendary version of DNN you'll want to do so in steps instead of directly to the version you want. SO much has changed since DNN 3, so this is more than likely why you're running into issues. However I'm certain there's a fix out there outlined in a DotNetNuke forum. I doubt that you're the first reported case of this issue.
Please let me know if you have any questions.
Thanks,
Ryan