Hi Uwe,
Having the same problem in Citrix with Notes crashing. I tried moving the cache dir but no luck. I've set the cache as non-persistent. I have a couple of question re your other steps:
Did you just disable DEP for the notes excutables (notes, notes2, nlnotes, rpclauncher, etc..) or the entire server?
Again, with the Citrix Hooks, did you disable them per exe? of so which ones?
Regards,
David