I saw this problem experienced by another elsewhere some time ago with the big Delphi Classics, so I ran a test, just out of interest using the Dickens collection (a little bigger than the Verne one) epub (not azw) as the source on a 64 bit, but only 4GB RAM machine.
I cannot remember if I tried an epub to epub conversion or an epub to mobi or azw now, but whatever it failed after a long run and I did not persevere.
My suggestion would be to go to the Kobo discount code sticky thread
https://www.mobileread.com/forums/sho...d.php?t=115233 in the Deals, Freebies and Resources forum and get a discount code for the Kobo store; you will then be able to buy an epub of Delphi's Verne for next to nothing (which is what I have done for a few I wanted).