can you tell me how to set it up to debug it?

I'm going to assume you've got Visual Studio 2005. The easiest way is to setup a local development install using the source version. Once you get that up and running and the AD source version of the provider installed you can add the project to source solution and debug from there.

I have something new to add. I have turned off Role Sync for now because it is causing problems for my users.  Now when I manually place a AD user in a role, I get an error message:

InnerException: String reference not set to an instance of a String. Parameter name: name
FileName:
FileLineNumber: 0
FileColumnNumber: 0
Method: System.Globalization.CultureInfo..ctor
StackTrace:
Message: DotNetNuke.Services.Exceptions.ModuleLoadException: String reference not set to an instance of a String. Parameter name: name ---> System.ArgumentNullException: String reference not set to an instance of a String. Parameter name: name at System.Globalization.CultureInfo..ctor(String name, Boolean useUserOverride) at DotNetNuke.Security.Roles.RoleController.SendNotification(UserInfo objUser, RoleInfo objRole, PortalSettings PortalSettings, String Action) at DotNetNuke.Security.Roles.RoleController.AddUserRole(UserInfo objUser, RoleInfo objRole, PortalSettings PortalSettings, DateTime effDate, DateTime expDate, Int32 userId, Boolean notifyUser) at DotNetNuke.Modules.Admin.Security.SecurityRoles.cmdAdd_Click(Object sender, EventArgs e) --- End of inner exception stack trace ---

This appears to be when it is trying to notify the user of the role change.  This only happens with users from AD and when I leave "Send Notification" checked. I can add any registered user to any group with no problem.