We've created this Forum Thread with some workarounds and advice to assist you in publishing you ebook.
Don't force authors to buy proof copies
Why does lulu insist on forcing people to buy proof copies?
"In order to approve your book for distribution, a proof copy of the most recent version of your book must be purchased....We want you to be 100% sure that your book is exactly the way you want it to be before it becomes available worldwide. Purchasing a copy for review is the best way to check the cover and the content before the final published work is sent into the distribution system."
I don't think many people are convinced by that. People know when they are being forced to buy something they don't have to. They know lulu is just trying to sell some books. I believe most authors are satisfied with the works they have submitted for distribution and don't make any changes afterwards.
Purchasing proof copies should optional. Authors should have the option to approve copies for distribution without being required to purchase proof copies. Createspace used to have the same requirement - you must purchase a proof copy to make sure everything is OK with your book - but they dropped it after they realized people knew better than that. And they have been getting even more customers because of that, among other reasons, of course, including books being listed on amazon.com almost right away - the next day or so and without charge.
If lulu continues with this policy, forcing authors to buy proof copies, they will continue to lose customers to their competitors, especially Createspace. Createspace even had free ISBNs long before lulu did. Now lulu is also giving free ISBNs. They also need to let authors approve their works without being required to buy proof copies. Those who want to buy proof copies will do so. But don't force those who don't want to just for their books to be approved for distribution.