in fact I was able to run e2fsck on the corrupted partition, BUT instead of specifying an offset of 32769, which made e2fsck to answer about a bad magic number, I used the offset 32768.
At this location I found a "valid" superblock. e2fsck worked quite a long time but recovered part of my configuration.
I still had to reinstall a small part of the system software, and was able to recover quite a lot of my lost files.
anyway I am about to burn several backup CD's in case
long live to linux