I need to install vagrant in headless ubuntu(Ubuntu 12.04.2 LTS- 64 Bit).Vagrant ver-v1.3.0 and Virtual box- 4.2.18. After adding the vagrant package box, when I am giving \"vag
A lot of these answers assume you're debugging a machine with a GUI, whereas the question is about a headless Ubuntu server.
The equivalent of looking in the Virtualbox GUI is the vboxmanage command, which can give you a log of info. Trying to do stuff that isn't working in Vagrant through VBoxManage directly will give you plenty of options to troubleshoot.
In my case just clearing up old VMs fixed my issues.
vboxmanage list vms
This will display the name and UUID of the VMs Virtualbox currently has registered. Grabbing the UUID of existing machines and clearing them up fixed the problems.
vboxmanage unregistervm $uuid --delete