You can follow the steps below to install the guest additions program on your ubuntu 11.10:
1) Create a temp directory in your home directory
2) Copy the whole file into the temp directory from /media/VBo..
3) Sudo apt-get install linux-headers-3.0.0-12-generic-pae
*Actually you get to make sure what kernel version on your machine
*After that, make sure your get "linux-headers-3.0.0-12-generic-pae" tree in "usr/src"
4) Install the guest additions utility.
具体编译log可以查看/var/log/vboxadd-install.log
/usr/bin/VBoxClient× 系列软件,可以运行。
启动桌面后,即可粘帖了