Well this explain your problem: optodisc are not the best choice.
I suggest you to buy better media. Among the best available there are verbatim and taiyo yuden. Verbatim are easier to find in stores, taiyo are easier to find online.
You can choose burning speed, and I suggest to burn these discs @8x or @4x.
With your liteon drive you can do a scan of one of these media. If you have time, can you post a scan of a problematic media? Select the "disc quality" tab in cd-dvd speed, select 4x as speed, and then press start.
After about 15 min, when scan end, save the image pressing on the little floppy button on high right corner and save as png.