Cant burn dvd-r discs !?!?!?

Hey ppl =)
I have a question about my nec 1300a that i have burn at least 350 dvd whit
and today it started to not burn dvd-r media
all burn programs says: Interpretation: Power Calibration Area Error
what can that mean?
I have the latest firmware and are using exactly the same media as before…
but then when i tried to burn whit +media it works and not whit - …=(
Happy for any answers
// LSD

Could be due to:
Dirty lens
bad discs
overheating drive
drive going bad

oki thx:)

If it shows the same problem for many media, very likely it is a hardware issue.
Is it still in the warranty period? If so, just returning it back for a replacement be the best solution.