Das Boot (1991) has just today been released on Steam and GOG.com. Regular price (AU)$9.95 but currently discounted by 33% (sale price ends 13 Nov). Should hopefully make things much easier for those who've had problems getting it to run from archive.org.
Edit: Having seen the one review on Steam, I'd recommend getting it from GOG, which lets you download the manual. Seems that the Steam version doesn't come with a manual.. (that or the reviewer was an idiot).