I have had reported this problem w/ 2.0.3 and Windows Authentication:

Users get thrown into the Registration screen, with a blank username (in Windows Authentication, registration fills user name for you - you cannot edit).

I have found that I can pretty reliably get this effect IF  I navigate to the Gemini instance (say http://gemini.mycompany.com/gemini ) - where login works fine thru WinAuth, and then from .../gemini/Main.aspx, edit the URL back to ..../gemini -- I then getted "popped" back into an "empty" user Register.aspx

The Error log holds (exactly one, and only one of) the following:

SESSION loss detected (GetUserID) -- no User Identity!

If I close, and bring up the browser this problem seems to go away (using IE 6).

I DO NOT expereince this with Firefox in anyway I have been able to detect.

I DID modify (with support's help)  gemini_getuserid()  SPROC (to manage floating domain name changes that are under progress in our intranet).

Since this was based on a skeleton Priority Support kindly provided, I can post here at your request (I have reviewed w/ several people, and do NOT see anything in it that would contribute to this - a user is found or not, with return values just as in the "stock" stored procedure, just additional logic; if this would have any effect because of error, I think it would register a person repeatedly....).

Thanks,

Yarko