Hello everybody. Thought I'd throw a few suggestions your way.
First, DVDPlayer doesn't natively support external drives unless there is an internal still connected and functional.
If you hex-edit the file that it uses to identify the player, however, you can change the word Internal to External and viola, you can use any external that your system can read with.
Now... ...if you don't know which file... read this, http://macenstein.com/default/2011/07/how-to-get-your-external-super-drive-worki ng-in-lion/
The file locations are similar across OSX versions.
Once you've done that...
Remember that mac wasn't designed to use lesser hardware. That said, most of the entire market would qualify as lesser hardware by their standards. However, you can get by with a few simple rules:
1. for burning dvd or higher size, 3gb ram and at least 4.5gb hard disk are necessary
2. Those drives that come with nero or similar are more compatible with the disc-burning architecture and will function with most mac apps that use it
3. you'll need a fast enough processor, 1.83ghz or higher for DL dvd, or blu-ray.
4. You'll need an app compatible with your media; toast, burn.app, etc.
If you experience issues try the following:
1. Clean out caches with ice-clean or similar
2. repair permissions
3. Use your system profiler and check the connection for info; if blank, the connection, the burner or the media is unsupported, so work backward (try more compatible media like cd or another format like swapping -r for +r), but only swap connections or burners if you are sure (if usb connection, try another powered port, try not using a hub, try a different wire; if internal, cannot swap either in most cases, but if sata, try using a usb-sata device to connect). When you've exhausted all the other possibilities, replace the burner. The most common problems of this nature can occur as hardware failure, like burnt pcb, or motor failure. By replacing the drive, if you still have a connection problem, you may have a deeper issue that requires more serious repair (repairing the computer).