[SQL]Unable to Modify a Maintenance Plan

Status;
1. Unable to modify any Maintenance Plans

2. Error Message showed like below


TITLE: Microsoft SQL Server Management

Studio

Could not load file or assembly 'msddsp, Version=9.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The system cannot find the file specified. (Microsoft.DataTransformationServices.Design)