Even if well used a super drive should last a few years minimum before any unreliable results start to show (but then the really, really cheap burners might last less time.) But then, even despite I have a lot of respect for Sony they can put out some poor individual drives. After speaking to a technician, there are the odd ones that just were lepricorns if you like ... don't last as they should. This can happen with any brand. The % it happens to depends on the brand.

As for your system. It's probably time for a complete check up using what ever utilities you have. Hopefully you also have some 3rd party ones like norton, diskwarrior, TechTool Pro, etc.
Even if not, restart the comp using your installation disk (hold down Apple & c keys whilst restarting.) Open the utilities folder & open Disk Utility. Now repair your computer.

How much spare space do you have on your comp. It might be time to make some more space. All OSX apps use VM which uses hard disk space whilst they're open.

It's just occured to me. Quit ALL applications whilst you want to burn a cd. Particularly LW! 256 MB ram is not much for OSX. ANd unfortunately LW & Java are not especially ram efficient. My LW has used up to 500 MB of ram on my comp at occasions. It has also used up to about 1.4 GB of temporary Virtual Memory of hard disk space.