You didn't say what virtual system you are running.
If it is V-box, after you start up the virtual system, look at the top for 'Devices' click, you should see any CD/DVD drives you have. Click on the check box to make it available to the virtual system.
It should then work from the virtual system.
Basically, the host owns the hardware, if you want the virtual system to use a device, you have to acquire it for the virtual system.
Hope this helps.
Last edited by camorri; 05-09-2012 at 08:54 AM.