I'm trying to install Windows Server 2008 R2 on a HP server, but I get this message:
Load driver - required CD/DVD drive device drivers is missing.
What could be the problem, and from where can I download this driver?
You don't mention the server model but every server will have a support pack available from http://www.hp.com (or a country specific site) with all drivers. There is also a SmartStart CD/DVD that will install needed drivers and assist with other tasks for OS install.
Again, available at http://www.hp.com. It works very well. and I would suggest using this. Just enter your model on the Drivers and Downloads page and select the correct OS and you will see a long list of tools and drivers.