I set up a website to use SqlMembershipProvider as written on this page.
I followed every step. I have the database, I modified the Web.config to use this provider,
I have checked the code over in the files you have sent me (thanks again for sending them through).
Note: I have not tested this since I have not installed the database etc..
However, I am pretty sure this is the issue.
You need to set the MembershipProvider Property for your ASP.NET controls. Making the definitions for them:
And..
This then binds the controls to the Membership Provider with the given name (which you have specified in the Web.Config.
Give this a whirl in your solution and let me know how you get on. I hope this works for you :)
I should also add, I know you shouldn't need to do this as the default provider is set, but I have had problems in the past with this.. I ended up setting them all to manual and all worked fine.