PDJ; Take a look at MTBman's post here

Is the fash drive new/old? Have you used it on the Vista machine before?  Is your Vista machine trying to use the flash drive as a ReadyBoost device (to speed up Vista)?

Could be a driver problem?

Because many USB flash drives have built-in software that runs every time you plug-in the drive into a PC yours might not have Vista compatable drivers.
Unfortunately the software loaded on these drives is incompatible with Windows Vista and not the drive itself.
You need to either update the software and download a Windows Vista compatible version or format the drive to delete everything that is included on it.

Also Jim, take a gander here

If the drive is found without errors, then Vista might not be assigning it a drive letter.
Right-click My Computer and select Manage.
Then select Disk Management.
See if the drive is listed there. If it is, right-click on the partition and select Change Drive Letter and Path...
Assign it a drive letter or change it to a different one. It may be trying to step on an existing drive letter or Windows may be confused on what to give it. If the last drive letter shown on a drive is H:, then give your flash drive I:. Once you save your changes, the drive should light up and be working. It is also possible that you need partition and format the drive.

If the drive doesn't show at all, check Device Manager for errors. You may have a conflict or need to update or load chipset drivers for your motherboard or USB card.

Hope some/any of what's here helps...if not, just hit me.

I moved the themes off the flash drive and into the CurFX folder where they are kept. I am not running them from the flash drive. 

Flash drive is fairly new, I have used it before on my Vista rig. It is not suitable for ready boost, according to my Vista lappy, and Cursor FX worked fine until I added oh, at least 50 CursorXP and FX themes all at once.

This flash drive was completely empty before I added the themes.

I suspect you may have a bad cursor file.Most likely an older cursor.

But...I have had to re-install CFX(free version)11,yes, eleven times.It will work for about three weeks and then lock up.I learned from experience that a simple uninstall/reinstall usually results in it locking up again immediately.I use Revo to uninstall and it finds 168 files and 272 reg entries left behind.Remove those and CFX is ok again for at least another three weeks.

Try that,then add your cursors one by one and see if you have a bad one.

I noted this in an e-mail to support,you may want to send in a ticket as well so they are aware of your trouble,Jim.

You give up on YM?

just a thought...is it possbile there's a permission issue with the cursor files?

Hope that job is going well. Out of orientation yet?