Getting duplicate entry"0" on primary key when click review from author side

When i try to submit an article, its run well until step 4, and then i click save and continue it should go to step 5, but suddenly i get error “duplicate entry 0 on primary key”, but the article is saved in ojs. The problem occurs when i want to review my article, same error occurs. Can you help me with this? Thanks.
FYI : i am using ojs 2.x