I give up - I'm fed up!!!
Lots of freaks were trying to help me, I clicked on lots of addresses that containes DVD-RAM-Drivers and always the same - they didn't work properly.
BHA is known, I updated the last driver I've written it, but I followed your hint about Toshiba. Something was new. I was just able to read. When I tried to write, the system said "the volume ist writing protect", when I tried to delete an existing file "file not fond". It's funny, isn't it?
This afternoon I was at my grandson and we tried to run my burner under XP64. No succsess. That filesystem was so destroied, that it was impossible to format the DVD-RAM-Disk with a GSA burner neither under XP nor WIN98. A Panasonic-HDD-Recorder was my last hope.
It seems to me that the developers say that it made no sense to built new updates for XP because VISTA and WIN7 was able to handle such volumes.
Thanks to all, I'm going to take back that burner to the seller!