In advance I can say that this isn't a case problem, I did type it in every case variation from VBoxManage to vboxmanage. Also installed the sources as Hmayag instructed, purged virtualbox and installed it again but I got the same problem. Sadly the guest I made hast too little disk memory so I tried using VBoxManage commands and it said that the command wasn't found. Browse to your guest additions folder. Connect and share knowledge within a single location that is structured and easy to search.
nest...