hello I build a module who increase stock on supplier invoices. Work fine on devel server but when I pun on work server I have this error. How can I corret this error?

Integrity Error

The operation cannot be completed, probably due to the following: - deletion: you may be trying to delete a record while other records still reference it - creation/update: a mandatory field is not correctly set

[object with reference: Purchase Order Line - purchase.order.line]