This may be a long shot but check your /etc/network/interface file. My installation stopped in a similar fashion to what you are describing. I came across some information in the wiki, unrelated to this, that mentioned that during the installation make sure that eth0 is your public facing network interface. I checked my interface file and found that only the ip address was listed on eth0. There was no gateway nor subnet mask listed plus the ip address was one from the range used on my routers dhcp server. I edited the interface file and added the subnet mask and gateway information. I then double checked the resolf.conf file to make sure it had at least one dns entry. Once I did this I rebooted the machine and it finished the installation and the orbiter appeared. I hope this works for you.
sounds like that solved anybodys problems here. I will reinstall beta2 again, and try this. I'm absolutely new to linux, can you give me a description what I have to type in my terminal or with what I can edit this file.
Thank you so far - maybe someone can add this to the beta2 wiki??? Just in case of a failed installation.