It seems that you are totally confused with this STB and all the software, I will try to help.
I see that you have used DCC to transfer the the "tar" file over to the /tmp folder but after that you seemed to get a mixed up on the next step. Using the remote on the Dreambox (hooked up to TV and TV is on) push the blue button and go down to "software management" that is where the file sent over with DCC (should be in the /tmp directory) the Dreambox will ask if you want to install that (it should be high lighted), you simply hit the OK button and it will install. After that post back with the cam you have and someone will respond to get you going.
Basically once the image is installed in the STB (Dreambox) everything else is done over your home network and unhooking the Dreambox to make changes are not necessary. You can do almost anything without unhooking the Dreambox from your home network. Mine runs 24/7 and it hasn't been shut down for over a month or so! It take some time to learn but well worth the effort for testing.