I laughed a little and give following suggession:
Create a page Sample.aspx which inharits from DotNetNetNuke.Framework.Pagebase and in page load manually authenticate a user host using UserController.ValidateUser method. That will help you login to the site in host account and then delete the page one you are done.
So these kind of problems where host or admin user cannot login with their accounts can be solved by this simple sample page. But be remember to change the host password because we have to use that password in clear format to write the code. Here is the code that I used:
Dim loginStatus As UserLoginStatus = UserLoginStatus.LOGIN_FAILURE
UserController.ValidateUser(PortalSettings.PortalId, "host", "xxx", PortalSettings.PortalName, "", PortalSettings.PortalName, AuthenticationLoginBase.GetIPAddress(), loginStatus)