Hi,
First of all, there is no problem with libebox, that's not an error. When the installation fails for any reason, it always purges libebox in order to left the system clean. Like if you were installed a regular Ubuntu Server. That's the reason why you didn't need to install Ubuntu Server. You could have login into the console right after the installation failed and have installed ebox as if you were doing it with an Ubuntu Server, editing the /etc/apt/sources.list and using apt-get install.
So you don't need to try it seven times, if it fails the first or the second time, the best you can do is fix the installation manually, you will lose much less time with that method.
Second, the real error that you are getting in the log you attach is that the dahdi-modules package can not be found. But I don't know why is that, I've tested the uploaded installer (1.3.10-2) several times and it always copies that package to /var/cache/apt/archives during the first stage of the installation and installs without problem in the second one. Maybe it's possible that the copy during the first stage is failing due to a read error with the CD or something like that, but I don't know. Have you checked that the .iso is downloaded correctly (md5sum)? Or maybe the CD is not well-burnt...
If you have any other useful data, like which packages have you selected or something like that it would be nice. But as I said, I can't reproduce that because the package that is missing in your installation is never missing in my tests.
Sorry for any inconvenience, we try to do our best but it's impossible for us to try our installers with all the possible configurations or in any hardware. Anyway, thank you very much for testing eBox.