First assignment — Update
it seems there were a lot of issues with the vagrant installation. Joris Nix has kindly updated the Vagrantfile, which should fix some of the problems you were experiencing. Please download the new version from the material section. For those who have already successfully installed vagrant, I would still recommend to run vagrant up --provision again with the new file: this should install missing packages that were not correctly installed during the first installation.
Apologies and have a good weekend!