reg. roles error

The following is the code to check whether the give role is existing
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Web;
namespace BLLayer
{
    public class UserManagement
    {
        public bool createrole(string strrole)
        {
            bool bstatus;
            if (!Roles.RoleExists(strrole))
            {
                Roles.CreateRole(strrole);
                bstatus = true;
          &nb ...