Error while executing DB procedure proxy

I am getting error 'Database error text: Insufficient privilege: Not Authorized ' when I call a database procedure proxy in a abap report program.

Can any one help?

CALL DATABASE PROCEDURE zdpp_oia_topandflop

EXPORTING iv_number = lv_number

IMPORTING et_top = lt_top

et_flop = lt_flop

I also tried calling a HANA procedure in an ABAP report program which works fine .

Thanks in advance !,

Sharada