Unable to delete products and PO's

Hi,
We have a bunch of products in SD that were in there before I became admin. When I try to delete them I get this error:

FAILURE :Error occurred while deleting Product.

Please report the problem to the system administrator, with the Error Code - 1,205,515,283,809.

I made sure that I have no assets assigned to those products.

I found out that I have some PO's with these products but I cannot delete those PO's also, I get this error:

FAILURE :Error occurred while deleting purchase order.

Please report the problem to the system administrator, with the Error Code - 1,205,515,381,872.

How can I delete these PO's so that I can delete those products?