After deeper tests, it's worth than i thought before!
Burning DVD+R and DVD-R wont start
burning DVD+RW 2.4x works fine at the beginning, then sometime does not finish and now i've got an error at the begining of the burning process.
Burning DVD+RW 4x wont start too
i've try to flash again the drive, no result! the drive is plugged on second ide channel as slave (dvd-rom as second channel master, and hard disk alone in first channel).
I don't know what to do now.