I can understand why it happens the first time but I'm surprised to see it go dry after 8 days. When I had one of these machines, it was working fine even with taking a 4 week holiday.
Initially when I got the machine, I complained about the lack of steaming power coming from this machine. The service center got me to check a few things:
1) the valve/spring in the water tank
2) open up the steam valve and run water through the group head (or the hot water wand.. i cant remember) - this is to bleed any air that's in the system.
Turns out it was just the wetness setting on my machine, so neither of these were solution to my problem, however it could be something you can check next time you think water isn't coming through.
Asides that - how often do you backflush your machine? I've seen machines where they are poorly maintained and it takes forever for the water to exit the group (hot water wand was fine though).