VDV brunign rplobem

I'm having a few problems burning DVDs using Thor, this is the second time I get this pop up warning when burning one; so far, both DVDs came out OK, but maybe there is a real problem in the near future.

Never used the DVD burner that much on the box, so I don't understand what it might be complaining about... Maybe lack of work :)

The burner is the DVD burner:

SONY DVD RW DRU-700A:

  Firmware Revision:  VY02
  Interconnect:   ATAPI
  Burn Support:   Yes (Vendor Supported)
  Profile Path:   VendorSupport.drprofile
  Cache:   2048 KB
  Reads DVD:   Yes
  CD-Write:   -R, -RW
  DVD-Write:   -R, -RW, +R, +RW, +R DL
  Burn Underrun Protection CD: Yes
  Burn Underrun Protection DVD: Yes
  Write Strategies:  CD-TAO, CD-SAO, CD-Raw, DVD-DAO
  Media:   No