Could not access Maintenance Plans in Management Studio

Error :
Method not found: 'Void Microsoft.SqlServer.Management.DatabaseMaintenance.TaskUIUtils..ctor()'. (Microsoft.SqlServer.MaintenancePlanTasksUI)

Investigation : 
SQL Server 2005 Management Studio is unpatched (9.00.1399)
Running SELECT @@Version shows the database engine is to be at Cumulative Update 9 (9.00.4294).

Solution :
Apply Service Pack to Management Studio

Ref : http://mbsturk.blogspot.com/2010/03/method-not-found-void.html