That's where the discs are made, not where you have to go to buy them!
As you can see from the 'Write Speeds' text, 2.4x isn't even an option on the MKM-003-00 media in that drive with that firmware.
If you're tried 4x, 6x and 8x and none of them work then you're out of luck.
Get some 2.4x MKM-001-00 discs as mentioned before and try again OR get yourself a new drive. You can pick them up for about