Moving records to Linked Server Db

HI

We have a job with 3 steps. The purpose of the job is to move the live data to OLAP db. Earlier the job was in a single step and it was working fine. Recently it was changed to 3 steps. 1st step for disabling indexes in the OLAP db; 2nd step for moving data and 3rd step to enabling indexes in the OLAP db.

Now the modified job with 3 steps is not working. Directly executing the script from Query windows works fine. But when executed as job the following error is thrown:

'EXECUTE AS USER' failed for the requested user 'dbo' in the database . The step failed.

The job owner & db owner is sa.

Kindly suggest. Regards Mohan Kumar VS

------- Script
use LiveDb 
go 

-- Step #1 : Disable Indexes
DECLARE @ConfigDb VARCHAR(500)
DECLARE @SQLQUERY NVARCHAR(2000)
-- get the OLAP DATABASE name 
SELECT @ConfigDb=config_value FROM tblConfiguration WHERE config_code='OLAP Database'
SET @SQLQUERY = 'EXEC '+ @ConfigDb + '.dbo.OLAP_Enable_Or_Disable_Indexes @IsDisable = 1 '
EXEC sp_executesql @SQLQUERY
GO

-- Step #2 : Copy data to OLAP
DECLARE @LastRunDate DATETIME
SET @LastRunDate = DATEADD(DD,-1,GETDATE())
EXEC dbo.OLAP_SP1 @LastRunDate
GO

-- Step #3 : Enable indexes using 
DECLARE @ConfigDb VARCHAR(500)
DECLARE @SQLQUERY NVARCHAR(2000)
SELECT @ConfigDb=config_value FROM config WHERE config_code='OLAP_DB'

SET @SQLQUERY = 'EXEC '+@ConfigDb+'.dbo.OLAP_Enable_Or_Disable_Indexes @IsDisable = 0 '
EXEC sp_executesql @SQLQUERY
go

-- 
ALTER PROCEDURE [dbo].OLAP_Enable_Or_Disable_Indexes(@IsDisable BIT = 0)
AS
BEGIN
    IF(@IsDisable = 0)
    BEGIN 
       IF  EXISTS (SELECT * FROM sys.indexes WHERE object_id = OBJECT_ID(N'[dbo].[OLAP_Tbl1]') AND name = N'IX_OLAP_Idx1')
         ALTER INDEX [IX_OLAP_Idx1] ON [dbo].OLAP_Tbl1 REBUILD

    END
    ELSE
    BEGIN
       IF  EXISTS (SELECT * FROM sys.indexes WHERE object_id = OBJECT_ID(N'[dbo].[OLAP_Tbl1]') AND name = N'IX_mdo_corporate_id')
         ALTER INDEX [IX_OLAP_Idx1] ON [dbo].OLAP_Tbl1 DISABLE
    END
END