Here are some reasons for update download failure:
1. You cannot connect to the Internet from the PC on which Lab is running. Launch your browser from this PC to make sure that you can make a connection.
2. The name and password on your DEFAULT Photogize account is invalid. The Lab update is harvested from WebServices and Lab uses the name and password of your DEFAULT account (the account that has a black check next to the folder in the left pane) to log into WebServices to get the update. Make sure that this name and password is valid or change your DEFAULT account to one that has a valid name and password.
3. You do not have enough disk space (~9MB) to download the update. Clear disk space and retry