Looks like tgidday is on top of this one.
You need to check your DMA mode. As tgidday said, just tick on reset DMA button in Fab. Good idea to read through both links...there's some good info and troubleshooting. The reset in Fab may not do it.

You have an LG burner. I don't know anything about Leader.
Here are the 3 LG models I found:
Videohelp

Most likely, your burner differs only in firmware, but your best bet is to go through the manufacturer for firmware updates.

This may be easier than straining your eyes and brain on the burn log.
(See the attached image below)
If you throw a disc in nero cd/dvd speed, just click on the Disc Info tab.
It'll display your burner and firmware, eg., Benq 1655 and BCGB
and below the MID (media code)

Anyway, let us know your MID and DMA mode, should be UDMA 2 or close.

Hope this helps.