Have Windows XP; downloaded iTunes 9, getting error message

still, it sounds like you may need to update the Gear Software driver.

Steps
1) Create manual restore point.
2) Download and install Gear update from here (Drivers Downloads tab).

Let us know if this helps or if you have any questions.

I don't know what "create manual restore point" means.

The Windows XP System Restore Guide is a great reference and includes information on creating a manual restore point and doing a system restore if necessary.

why should I trust this Gear's driver download? Is it trustworthy?

Good questions. When I first heard of Gear I thought the same thing. It turns out that Gear Software is the company that provided the drivers that are already on your system which are included with iTunes. If you do a search for gearaspi* on your hard drive you should see at least one, probably two, files from Gear already on there. The download on that link in my first reply is the newest update.

A useful way to find out if you can trust a site is to use the Web of Trust plugin. It's like McAfee's SiteAdvisor but it seems to me, and many others, to do a better job of evaluating websites.

You're welcome, still. Let us know how it goes when you get a chance.