I want to give an update, I got the DVD player to work properly by changing the DVDframework file. I changed all indications of "Internal" to "External". As posted on
Modify the DVDPlayback framework that DVD Player uses, so that it will recognize your external drive as a valid DVD playback device. Keep in mind that if you do this the system may no longer recognize the internal drive, so I only recommend it for systems where the internal drive no longer works and your only option is to use the external player.
Download a hex editor that has text-searching capabilities (0xED is a useful one).
Go to the folder /System/Library/Frameworks/ and back up the file "DVDPlayback.framework." If you have a regular Time Machine backup of the system that should suffice, or you can copy the file to your desktop.
Open 0xED or your preferred hex editor and use it to open the following file:
Using the editor's searching options, search for the text "Internal" and replace all occurrences of it (there should be four) with the text "External" and save the file. If you cannot edit the text with your program, then locate the hex code for the word "Internal" (which is "496E7465726E616C") and replace it with the hex code for the word "External" (which is "45787465726E616C").
Close the file once saved, and then run a permissions fix on the boot drive using Disk Utility. Then restart the system and you should now be able to play DVDs off the external drive using DVD Player.