It didnt show up immediately. It showed that the provider had succesfully installed. I got the error as soon as I clicked return.
I was just able to at least get the site working again by commenting out in web.config the last key:
<httpModules>
<!-- add name="Authentication" type="DotNetNuke.HttpModules.AuthenticationModule, DotNetNuke.HttpModules.Authentication" / -->
<add name="ScriptModule" type="System.Web.Handlers.ScriptModule, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" />
<add name="Compression" type="DotNetNuke.HttpModules.Compression.CompressionModule, DotNetNuke.HttpModules" />
<add name="RequestFilter" type="DotNetNuke.HttpModules.RequestFilter.RequestFilterModule, DotNetNuke.HttpModules" />
<add name="UrlRewrite" type="DotNetNuke.HttpModules.UrlRewriteModule, DotNetNuke.HttpModules" />
<add name="Exception" type="DotNetNuke.HttpModules.Exceptions.ExceptionModule, DotNetNuke.HttpModules" />
<add name="UsersOnline" type="DotNetNuke.HttpModules.UsersOnline.UsersOnlineModule, DotNetNuke.HttpModules" />
<add name="DNNMembership" type="DotNetNuke.HttpModules.Membership.MembershipModule, DotNetNuke.HttpModules" />
<add name="Personalization" type="DotNetNuke.HttpModules.Personalization.PersonalizationModule, DotNetNuke.HttpModules" />
<!-- <add name="Authentication" type="DotNetNuke.Authentication.ActiveDirectory.HttpModules.AuthenticationModule, DotNetNuke.Authentication.ActiveDirectory" /> -->
</httpModules>