This problem was solved for me by simply plugging into a USB port on the back of my Dell XPS 710 instead of the front USB port.
Here is information I received from Wacom Tech Support:
Make sure your tablet is plugged directly in the back of the computer and not through a hub or external USB adapter.
Download and save to your desktop this driver:
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http://www.wacom.com/productsupport/download.cfm?id=175& product=XD>
Go to control panel > Add or Remove Programs.
Scroll down to Tablet and uninstall the drivers.
On restart, click Start > Control Panel > Administrative Tools > Services > Terminal Services Double click on Terminal Services to bring up the properties window.
In the middle of the window it shows the Startup Type. Select Automatic. Just below that under Service Status it should say "Started". If it doesn’t click on the Start button. Click Apply and OK.
Disable any anti-virus, firewall, or ad ware software you have and close all open applications. Double click on the downloaded drivers and go through the installation wizard.
Click on Start > All Programs > Wacom Tablet > Tablet Preference File Utility. Click on Remove all preference files.
Finally, lets reset the preferences for Photoshop. This one is a bit tricky. When you launch it, you’ll have to immediately press and hold Shift, Ctrl, and Alt. This will bring up a window asking if you want to delete the preferences. Click on yes and CS3 will be back to the way you first installed it.
