To view and change the FTP settings click menu item Tools - Settings... and select the FTP settings tab.
You can change the value of the timeout depending on your connection speed. Slow Internet connection may require greater timeout value up 30 or even 45 seconds. For fast connection speed 10 - 15 seconds is enough.
How does the timeout work?
When the gallery file upload is stopped for some reason, Extreme Thumbnail Generator will wait TIMEOUT seconds for the upload to resume and if nothing happens it shows the FTP error dialog which allows you to choose whether you want to retry upload this file, skip it or stop upload the gallery.
If you are connected to the Internet through a proxy server, then check the Use FTP proxy box and enter the parameters of your proxy server, your proxy user name and password.