The only way to exclude a damaged burner as cause is to try a proven quality disc like Verbatim.
Outside EU and US, genuine MCC Verbatims are often hard to get, if at all. In many of these countries, Sony is among the best stuff you can buy (assuming these are genuine) - most other media there is often crap or fakes.
My personal experience with Sony isn't bad. Better than those (MiT) Verbies I bought, that seemed to be originally targeted to the eastern european and turkish market. :Z