Well, I saw that you had no replies to your question after 1 day (due to lack of information) and so tried to elicit more details from you in the hope that someone could help with your problem.
I believe XBOOT can use either grub4dos or syslinux and from your last post I assume you chose syslinux??? Still no idea what ISO/payloads you were trying though???
We are still no wiser and still nowhere near understanding the original problem or solving it.
By '32-bit' and '64-bit', I assume you are talking about the processor?
So are you saying that XBOOT did not boot at all, or tried to boot but something happened (what exactly)?
Does an XBOOT drive (that shows the same problem) boot OK from a VM (e.g. VBox with 64-bit CPU configured)?
Are you sure it is the 'bitness' of the system that is the problem - if so why do you think that, rather than the problem being to do with the system chipset or BIOS?
P.S. XBoot is no longer supported as the author (shamur) has passed away and we have no sources. You could try my Easy2Boot project instead which is supported (even after a heavy Saturday night!)