I see lot of people are having problems with the new Zygor guide that is using Tomtom. Just follow my steps here and it should work :-)
1. Click the Options button at the bottom right of the big guide window
2. In the options, on the left, click the "+" sign next to Zygor's Guide in the list.
3. Click the "Map-related settings" option on the left that is shown
4. In the options to the right, make sure "TomTom" is selected in the dropdown menu.
And it works, enjoy ;-)
You should realy buy this guide if you like it (I did), great support and fast updates.