DualSelect error

Jan 18 at 6:24 PM
I'm getting an error "The type 'ChoiceList<TItem, TValue, TDisplay>' exists in both 'MVC4ControlsToolkit, Version=3.0.0.0, Culture=neutral, PublicKeyToken=b6277d1c804403e7' and 'MVC5ControlsToolkit, Version=3.0.0.0, Culture=neutral, PublicKeyToken=b6277d1c804403e7'

generating at this point in my code:
...ChoiceList<TMTFranchiseList...
<div>

            @{ var groupSelect = Html.DualSelectFor(m => m.Groups,
                     new ChoiceList<TMTFranchiseList, int, string>(
                     CallReport.AllGroups,
                     t => t.Region,
                     t => t.Region));
                }
            <table>
                <tr>
                    <td colspan="3" valign="middle" align="center">
                        @groupSelect.ClearSelectionButton("Unselect All")
                        @groupSelect.UnSelectButton("Move Left")
                        @groupSelect.SelectButton("Move Right")
                        @groupSelect.SelectAllButton("select All Roles")
                    </td>
                </tr>
                <tr>
                    <td valign="middle" align="center">
                        Available Groups
                    </td>
                    <td valign="middle" align="center">
                        Selected Groups
                    </td>
                    <td valign="middle" align="center"></td>
                </tr>
                <tr>
                    <td valign="middle" align="center">
                        @groupSelect.AvailableItems(
                            new Dictionary<string, object>
                            {
                                {"style", "height:150px; width: 100px;"}
                            }
                         )
                    </td>
                    <td valign="middle" align="center">
                        @groupSelect.SelectedItems(
                            new Dictionary<string, object>
                            {
                                {"style", "height:150px; width: 100px;"}
                            }
                         )
                    </td>
                </tr>
            </table>
        </div>