Have you tried to set your ruby version using the alternatives system?
update-alternatives --config ruby
Type: Posts; User: madAndroid; Keyword(s):
Have you tried to set your ruby version using the alternatives system?
update-alternatives --config ruby
I was experiencing this until I downloaded the VirtualBox Additions ISO under the downloads section on the VirtualBox website - VBoxGuestAdditions-3.1.7
hope this sorts the problem out for you too...