Which version of DotNetNuke were you on when you were using 5.0.2? I'll have to do a test to see if I can sort out why you and Francisco are having problems. Francisco has the same environment as I have except I'm running SQL 2008 on our production site.

I haven't been able to recreate the problem with your setup Francisco as that's the exact same setup that I've got here in production except we're running SQL 2008 but that wouldn't affect only seeing one login version or prevent the automatic redirection to windowssignin.aspx.

Can you send me a screen shot of your settings and a copy of your web.config (with any username/passwords blanked out) to michael.john.horton@gmail.com so that I can take a look at it.

any resolutions to this? We're using the Active directory authentication and every customer that hits the website gets a 500 error.

The link in the address bar is 

http://domain.com/DesktopModules/AuthenticationServices/ActiveDirectory/WindowsSignin.aspx

If I go back again and type in the domain again "domain.com"

It doesnt do it.