I posted a question to TomTom support and received the following reply:
Thank you for contacting TomTom Customer Support. My name is Shellie and it is my goal to provide you with an exceptional customer experience.
We apologize that you are not receiving updates through TomTom HOME. We recommend that you try the following FAQ:
www.tomtom.com/7399
If you have any further questions or comments, please e-mail or call us at 866-486-6866 Monday through Friday, 8:30 AM until 7:00 PM EST. Thanks again for writing. At TomTom we believe in showing you the way the easy way.
With Best Regards,
Shellie and The TomTom Customer Support Team
Here is some of the text from the link:
Question
When installing the QuickGPSfix through HOME I receive an error. Is there a solution?
Answer
When performing the QuickGPSfix through HOME, some problems may occur if this directory does not exist, or if the directory has been corrupted. To resolve this issue, take the following steps.
1. With your TomTom device connected to your computer, go to My Computer and double-click your TomTom device (device will be listed under Devices with Removable Storage).
* For Mac users, the device will mounted on the Desktop.
2. Look for a folder called ephem.
2a. If the folder does not exist, create a new folder (File > New > Folder or File > New Folder ) in this location and name it "ephem". Retry the QuickGPSfix through HOME.