Hi Bear,
The easiest correction to submit is to add points of interest. Do do so, I suggest you go to the location of interest(for example, a restaurant) with your GPS and mark it as a "favorite" on your GPS. Then use the Mapsource program to download your favorites to your computer. In Mapsource, correct the name and icon for the location. Then upload the Mapsource file to the Cenrut folder (as a compressed file).
For roads, you can also use most GPS devices to record your tracks. The tracks are imported to Mapsource, then cleaned up and submitted to the Cenrut site. We have explanatory documents in Spanish, but nothing in English.
Does this answer your question?