Benq DW 822A firmware trouble

Bought this drive a couple of months ago, working painlessly. Then came winxp sp2 and another firmware and all of a sudden things don’t work as they used to. I couldn’t burn an iso getting an errormessage that the disc wasn’t compaible with the source data (using sonic’s RecordNow which is bundled with the drive and works brilliantly). I downgraded the firmware as instructed on Benq’s website from b3kc to b3jc, chose the not d/l option and upgraded again. Same problem. Upgraded the px engine, same problem. Tried the Brothers’ firmware, same problem. After some up- and downgrades I now finally succeeded to burn a working disc but I still didn’t succeed to upgrade the Recordnow software from 6.7 to 7.2 with the upgrade available on Benq’s website. Errormessage: required dvd/cd drive could’nt be found. I don’t get it. Can anyone help?