Close all unnecessary programs before burning. If you keep getting the 'unable to lock volume for exclusive access' error then please read the FAQ on how to solve this problem.
As it was said on your other thread about this same problem, your discs aren't being booktyped correctly. Use the Book Type dialog to manually set the booktype to DVD-ROM before burning (use the EEPROM option to save this preference on the burner's memory). Alternatively you could add ATAPI iHAS120 6 to Lite-On OEM in the Advanced settings of the Book Type dialog.