I believe that part of the problem I am having is a consequence of hte following process:
1) I am able to set up a new account.
2) I log out the account.
3) I go to log in again using the account details.
4) I manually go into database and check the new User details have been put into the database.
5) I try to log in and get a message "Login failed for xxx@xxxx.com"

Note that I have swapped the Onit around as recommended already.

I think this is where it is happening - I believe it may be returning null:

PhilePrincipal newUser = PhilePrincipal.ValidateLogin( EmailAddress.Text, Password.Text );
            if (newUser == null)

Any suggestions on how I can check this? Note that I am a newbie with a few months experience - so keep it as simple as you can!

Apologies - I got confused and put this in the wrong place. I wont repost... this refers the problem with Cast.