I could also manage to get into the HD - at least once. It's very strange: when the hdd_Driver came up for the first time, I got about 5 of the "Invalid filename size" messages. I clicked them away and copied a test file on the hd - just to see if the prog works as expected. Well, copying was ok and I explored the filesystem a bit - then it crached.
Now, I can not access the disk any longer with hdd_driver - I get hundreds of those "Invalid size" boxes. Clicking them away doesn't help 'cause sooner or later it will crash... Nothing seems to help: rebooting, other dll's... At least, the disk is not messed up - it still loads the dashboard in my xbox (phew)
Shit, I was so close...