Magento SQL error

SQLSTATE[23000]: Integrity constraint violation: 1452 Cannot add or update a child row: a foreign key constraint fails (mlvcom_mlvstore.affiliateplus_account, CONSTRAINT affiliateplus_account_ibfk_1 FOREIGN KEY (customer_id) REFERENCES customer_entity (entity_id) ON DELETE CASCADE ON UPDATE CASCADE)

I tried flushing cache but I dont really know Magento that great. Can anyone help?

the error message says that you’re trying to add an affiliate account for a customer that doesn’t exist in the customer entity table

But I created an account and got the email that let me login. But when I try to set up the affilate account then I get error.