Error when install VBox Guest Additions in CentOs 5.5 .. 6.4 I found this solution to complete installation and access shared folder

shared_folder_centos_virtualbox.txt

# The VirtualBox documentation[1] for how to install guest additions
# for Linux on a virtual host is somewhat messy. So here is what
# I did to make it work.
 
# Install the packages required
yum update
yum install gcc kernel-devel make
 
reboot
 
# Click VirtualBox menu: Devices/Install Guest Additions...
 
# Mount the ISO image with the guest additions
# Pay attention: We are run as sudoer
mkdir /cdrom
mount /dev/cdrom /cdrom
 
# Install guest additions
/cdrom/VBoxLinuxAdditions.run

# Reboot to complete installation
reboot

# Share a folder from the VirtualBox control panel, giving it a share name.
 
ls /media/sf_<share_name>
 
 
# You could always mount the directory yourself as well
mkdir /a_folder_name
mount -t vboxsf the_share_name /a_folder_name