The problem is XP x64 was never really intended for widespread use. That's why it was only ever sold as OEM, and Microsoft killed off support for it before SP3 came along. XP x64 was just meant to hold over people who had specific need for a 64-bit OS that were getting impatient over how long Vista was taking to come out.
These are the kinds of issues, along with poor driver support, that comes with using an OS like XP x64. So if that is a problem, I'd suggest you figure out some kind of alternate situation. I'd recommend moving away from XP x64 regardless since it has not been supported for quite some time, and there are a number of security issues in XP that have not been, and will not be, fixed in the x64 version.
I have Dragon Natural Speaking 11.5 and When Installing it tells me it "IS NOT COMPATIBLE WITH 64BIT OS"?
Any KNOW if there is a Dragon Natural Speaking Version that is Compatible with XP Pro 64bit?
Need Help.
Thanks;
Sugarbear246

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic