I can not start the Setup
Please, check that you have an active Internet Connection and tap the "Retry" blue button. Your GPS should be active too, so active it, and tap the "Retry blue button if you got a red light.
Slow Internet connections such as GPRS or EDGE (G - E) could cause timeout problems at time of download GPS Aiding Data. Please, whenever you can, try to use a fast Internet connection.
Once you got green light at "Checking Internet connection..." and "Checking GPS connection..." you will be able to start the "Setup".
I got a red light checking for root
Don't worry if your device in non rooted. You can continue with the "Setup". But take in mind that some advanced features will not be available.
Problems downloading XTRA Data and/or LTO File
This can be due to many factors. Among them, a slow Internet connection, an incompatible device, a device misconfigured, and so on.
The first thing to do, is to make sure that you have a fast Internet connetion (Mobile Internet connection preferred) and tap the "Retry" button. If the problem persist, try to disable your WiFi and restart your device (this is because some devices cannot download XTRA data using WiFi connection).
Can be my device incompatible?
Almost all GPS Chip's currently used in Android devices are compatible with XTRA and LTO. Most likely your problem is a misconfiguration. If you are using a "Samsung Galaxy S" try to run "GPS Doctor" and then run one more time the "Setup". "GPS Doctor" need a rooted device to work.
"GPS Doctor" didn't fix my problem...
If your are using a "Samsung Galaxy S" you may have an old ROM with an old MODEM and GPS Driver. That may be the problem. Try to update your device using "Kies" or "Odin".