And don't forget the help file.
As for the debug log I agree with BloodSword, and for the website: I took a look around and found many pages in German where one could download MyDefrag, including a more or less detailed description. I think that should suffice for most people.
I think a proper translation of the installer text is more important than the manual, so people know what they're actually installing.
On the other hand, I know a lot of people who just click on continue without reading the pages (a lot of not needed toolbars and advertisement can be found on these PC's