the following error is because of fiscal year variant..
copy all the fiscal year variant from ECC using OB29 tcode.
open the BI system paste all the fiscal year variant in OB29.
then in RSA1 --> Source systems --> right click of the ECC source system-->Transfer Global Settings-- > check the fiscal year variant and update tables--> execute it.
again load the data to DSO and activate.. will be successful....enjoy SAP