Error, "Unable to cast object of type 'System.DBNull' to type 'System.String'" when opening Storage tool (4317488)

When try to open the storage tool in Toad I get the following error:

System.InvalidCastException Unable to cast object of type 'System.DBNull' to type 'System.String'. Stack Trace: at Quest.Toad.SqlServer.Trl.Databases.DatabaseCapacityTrl.GetCapacityList() at Quest.Toad.SqlServer.Dov.StorageManagement.AllDatabaseListControl.EndReload() at Quest.Toad.SqlServer.Dov.StorageManagement.AllDatabaseListControl._databaseCapacityTrl_Updated(Object sender, EventArgs e) at Quest.Toad.Cache.LiveCache.UpdatedProxy(Object sender, EventHandler handlers)