Transorm Pivot Query Error in Excel – Class not registered

I was generating pivot content in excel using Transform Query. I am getting an error “Class not registered” when executing the Query using a ADODB Connection with the Command Con.Execute.

Could any please suggest me whether any DLL in my OS has been corrupted or steps for solving the issue. for reference i have pasted the Query below.

Thanks in Advance.

TRANSFORM Sum(Q1.[Total]) SELECT [TaskID],[Task] FROM (SELECT Q2.TaskID, Q2.Task, Q2.BUID, Q2.BU, [Weekly BU Summary$].Total FROM (SELECT A.TaskID, A.Task, B.BUID, B.BU FROM [Master$] AS A,[Master$] AS B) Q2 LEFT JOIN [Weekly BU Summary$] ON (Q2.BU = [Weekly BU Summary$].[Business Unit]) AND (Q2.Task = [Weekly BU Summary$].Task) ORDER BY Q2.BUID) Q1 GROUP BY [TaskID], [Task] PIVOT Q1.[BU]