Webgui logon screen re-loads

I am trying to get my WEB AS 6.40 webgui installation working, but I am having problems.

If I don't have the SSO2 parameters installed, the user and password fields are "greyed" out (is this normal??), but the basic authentication works with the popup box to login with. Log in, see webgui no problem.

Once I configured SSO2 and HTTPS, the login box comes up without complaint, and the login and password fields are no longer grey, and basic authentication is no longer available. All should be good, but it is not. I enter my login and password, and then the screen breifly flashes "staring application", and then immediately returns to the login screen. I know it is communicating to R/3 because if I enter the wrong password it knows. If I enter the right one, I get the starting application screen for a moment, and then right back to the login screen.

Any ideas on what might be causing this? Are there some logs I can go look at besides the logs and trace files in SMICM?

Thank you,

John Rhea