System.Reflection.TargetInvocationException: Property accessor 'RoleID' on object 'ChemManager.BusinessObjects.Security.Role' threw the following exception:'Object does not match target type.' ---> System.Reflection.TargetException: Object does not match target type.

using System;
using ChemManager.Attributes;

namespace ChemManager.BusinessObjects.Security
{

    public class Permission : IChangeLog
    {

        private static readonly log4net.ILog log =
            log4net.LogManager.GetLogger(System.Reflection.
            MethodBase.GetCurrentMethod().DeclaringType);

        public Permission()
        { }

        public override string ToString()
        {
            return _permissionName;
        }

        public virtual event EventHandler PermissionIDChanged;
        public virtual event EventHandler PermissionNameChanged;
        public virtual event EventHandler DescriptionChanged;
        public virtual event EventHandler LongDescriptionChanged;

        private long? _permissionID = null;
        private string _permissionName = null;
        private string _description = null;
        private string _longDescription = null;

        private long? _nhVersion = null;
        public virtual long? NhVersion
        {
            get { return _nhVersion; }
            private set { _nhVersion = value; }
        }

        private DateTime? _created = null;
        public virtual DateTime? Created
        {
            get { return _created; }
            private set
            {
                if (_created == null)
                    _created = value;
            }
        }

        private User _createdBy = null;
        public virtual User CreatedBy
        {
            get { return _createdBy; }
            private set
            {
                if (_createdBy == null)
                    _createdBy = value;
            }
        }

        private DateTime? _lastUpdated = null;
        public virtual DateTime? LastUpdated
        {
            get { return _lastUpdated; }
            private set { _lastUpdated = value; }
        }

        private User _lastUpdatedBy = null;
        public virtual User LastUpdatedBy
        {
            get { return _lastUpdatedBy; }
            private set { _lastUpdatedBy = value; }
        }

        [KeyField()]
        [ListField(0)]
        public virtual long? PermissionID
        {
            get { return _permissionID; }
            private set
            {
                _permissionID = value;

                if (PermissionIDChanged != null)
                    PermissionIDChanged(this, new EventArgs());
            }
        }

        [SearchField(0)]
        [ListField(1)]
        [FieldDescription("Permission Name", "Name")]
        public virtual string PermissionName
        {
            get { return _permissionName; }
            set
            {
                if (_permissionName == null)
                {
                    _permissionName = value;

                    if (PermissionNameChanged != null)
                        PermissionNameChanged(this, new EventArgs());
                }
            }
        }

        public virtual string Description
        {
            get { return _description; }
            set
            {
                _description = value;

                if (DescriptionChanged != null)
                    DescriptionChanged(this, new EventArgs());
            }
        }

        public virtual string LongDescription
        {
            get { return _longDescription; }
            set
            {
                _longDescription = value;

                if (LongDescriptionChanged != null)
                    LongDescriptionChanged(this, new EventArgs());
            }
        }

    }

}

<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.0">
  <class name="ChemManager.BusinessObjects.Security.Permission, ChemManager "
         table="fw_permission">

    <id name="PermissionID" column="permission_id" type="long">
      <generator class="sequence">
        <param name="sequence">fw_permission_seq</param>
      </generator>
    </id>

    <!-- Standard Columns -->

    <version name="NhVersion" column="nh_version" type="long" />
    <many-to-one name="CreatedBy" class="ChemManager.BusinessObjects.Security.User, ChemManager" column="created_by" />
    <property name="Created" column="created" type="DateTime" />
    <many-to-one name="LastUpdatedBy" class="ChemManager.BusinessObjects.Security.User, ChemManager" column="last_updated_by" />
    <property name="LastUpdated" column="last_updated" type="DateTime" />

    <!-- End Standard Columns -->

    <property name="PermissionName" column="permission_name" type="String" />
    <property name="Description" column="description" type="String" />
    <property name="LongDescription" column="long_description" type="String" />

  </class>
</hibernate-mapping>

        public static IList SearchByExample(object searchObject)
        {
            ICriteria c =
                Connection.Session.CreateCriteria(searchObject.GetType());
            NHibernate.Expression.Example e =
                NHibernate.Expression.Example.Create(searchObject);

            e.ExcludeZeroes();
            e.ExcludeNulls();
            e.IgnoreCase();
            e.EnableLike(NHibernate.Expression.MatchMode.Start);
            c.Add(e);

            IList result = c.List();

            return result;
        }

private IList _searchResults = null;
_searchResults = Data.Search.SearchByExample(_searchObject);
dgvResults.DataSource = _searchResults;

<?xml version="1.0" encoding="utf-8" ?>
<hibernate-mapping xmlns="urn:nhibernate-mapping-2.0">
  <class name="ChemManager.BusinessObjects.Security.User, ChemManager"
         table="fw_user">

    <id name="UserID" column="user_id" type="long">
      <generator class="sequence">
        <param name="sequence">fw_user_seq</param>
      </generator>
    </id>

    <!-- Standard Columns -->

    <version name="NhVersion" column="nh_version" type="long" />
    <many-to-one name="CreatedBy" class="ChemManager.BusinessObjects.Security.User, ChemManager" column="created_by" />
    <property name="Created" column="created" type="DateTime" />
    <many-to-one name="LastUpdatedBy" class="ChemManager.BusinessObjects.Security.User, ChemManager" column="last_updated_by" />
    <property name="LastUpdated" column="last_updated" type="DateTime" />

    <!-- End Standard Columns -->

    <property name="UserName" column="user_name" type="String" />
    <property name="DisplayName" column="display_name" type="String" />
    <property name="ActiveDirectorySID" column="active_directory_sid" type="String" />
    <property name="PrimaryMachineName" column="primary_machine_name" type="String" />

    <list name="Roles" cascade="all" generic="true" table="fw_user_roles">
      <key column="user_id" />
      <index column="list_index" />
      <many-to-many class ="ChemManager.BusinessObjects.Security.Role, ChemManager" column="role_id" />
    </list>

    <list name="Impersonations" cascade="all" generic="true" table="fw_user_impersonations">
      <key column="user_id" />
      <index column="list_index" />
      <many-to-many class ="ChemManager.BusinessObjects.Security.User, ChemManager" column="impersonate_user_id" />
    </list>

  </class>
</hibernate-mapping>

   at System.ComponentModel.ReflectPropertyDescriptor.GetValue(Object component)
   at System.Windows.Forms.DataGridView.DataGridViewDataConnection.GetValue(Int32 boundColumnIndex, Int32 columnIndex, Int32 rowIndex)

   at System.Reflection.RuntimeMethodInfo.CheckConsistency(Object target)
   at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture, Boolean skipVisibilityChecks)
   at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
   at System.ComponentModel.ReflectPropertyDescriptor.GetValue(Object component)

?_searchResults[0].GetType().FullName
"CProxyTypePermissionSecurity_INHibernateProxy1"

?_searchResults[1].GetType().FullName
"ChemManager.BusinessObjects.Security.Permission"

?_searchResults[2].GetType().FullName
"CProxyTypePermissionSecurity_INHibernateProxy1"