HELP: Authenticating users based on role

Hi,

I have 2 roles namely "Creative" and "Client". Ialso have 2 login pages in their respective folders creative and client. In my login page that is in the creative folder, I would like to authenticate the user only if he is in the "Creative" role even though the user account exists in the db. I am using the Membership system to login my users and have used the Login control with the following code but the login seems to fail even though the user is in the "Creative" role. Much help will be appreciated:

  private bool ValidateUser(string UserName, string Password)
{
bool valid = false;
if (Membership.ValidateUser(UserName, Password))
{
if (Roles.IsUser ...