Architecture :: Access Membership And Profile Data From C# Windows Service?

I want to access membership and profile objects and wants to access profile properties that I have defined in my web app web.config file, from a windows service. I have used this code

foreach (MembershipUser user
in Membership.GetAllUsers())
{
ProfileCommon userProfile = profile.GetProfile(user.UserName);
}

But its giving the followin errors The type or namespace name "ProfileCommon" could not found (are you missing a using directive or an assembly reference?) The type or namespace name "MembershipUser" Could not found (are you missing a using directive or an assembly reference?)