The problem here is that my script just generates links to map tiles on the Google Maps server, but it doesn't know if these tiles exist since they are fetched by GE after the network link has been refreshed.
The whole world seems to be available down to level 8 with the following exceptions: - Canada: level 2-0 - Japan: level 0 - UK and Ireland: level 0 - USA: level 1-0
The simplest solution to the problem is in the attached KMZ - just sets the minimum zoom level to 8. This should work anywhere but it's also very boring, perhaps people can use it for troubleshooting. If you use the script in a certain area you might try out the smallest zoom level that you can use without errors and then use this number as the ZMIN parameter in the network link location.
Now I could try to limit the zoom factor depending on the area, but then if Google Maps adds new data people couldn't use it before I change the script. (and people couldn't use the script to look for areas with new data).
Another suggestion would be that GE removes the "Could not load image" message boxes - the "Image not found" picture should be enough to inform the user. Maybe there's also a Windows utility which can automatically click away certain message boxes...