Trouble with external CD/DVD drive

Hi all. This is my first post on Apple Support.

I have an external CD/DVD burner grabbed from my old laptop. I bought an USB adapter box to get this drive working on my iMAC (21.5'' Mid-2011 with Lion 10.7.5).

When I attach the drive to the iMAC and insert a CD (or DVD) I can see it's content in the Finder but I'm unable to do anything with the files. No way to open or copy them. If I try to open a file the drive spins up but nothing happens and the application hangs until I eject the disk. Then I get the error "Unable to open file". Same thing when trying to copy a file.

The same drive with the same CD (or DVD) works properly when attached to other PCs with WinXP or Win7.

Moreover, the drive attached to my iMAC works properly if I access it through a WinXP copy running on Parallels.

What can be the issue?

Thanks in advance.