Well, I had several problems with my drive, so I patched the newest firmware GSBC with OmniPatcher with the attached settings, emoved every drive-related stuff from hardware manager and did 2 reboots.
Everything works fine, the 451s reads CDs from magazines, DVDs from magazines, burned CD media (R, RW) BUT no previous 100% working DVD+Rs.
I have all my backups on CDs and DVDs. 60 CDs and 10 DVDs yet - would be terrible if I could not get the data back!
I have "resetted the learned media", "repaired the eeprom checksum" (no errors found) after that. Still the same...
Would be grat if somebody could tell me a solution or a tip. Thx!