I just bought the add-on "Shipwrecked" on Humble Store (https://www.humblebundle.com/store/p/dont_starve_shipwrecked_storefront?hmb_source=search_bar). Unfortunately, there is no installation instruction included. So I unpacked the "shipwrecked_x64.tar.gz" content into my main Don't Starve directory (I bought Don't Starve at gog.com). Checking the files, they seem to be at the right place because DLC0002 is in the same subdirectory as "DLC0001" and "manifest_dlc0002.json" is in the same main directory as "manifest_dlc0001.json". When I try to start Don't Starve it instantly crashes on my Ubuntu 14.04 LTS 64 Bit Linux. It ran without problems before I unpacked the shipwrecked files in the directory.
The attached "DontStarveOutput.txt" shows the console output.
Install Don't Starve from gog.com (https://www.gog.com/game/dont_starve), unpack "shipwrecked_x64.tar.gz" from Humble Bundle Shipwrecked (https://www.humblebundle.com/store/p/dont_starve_shipwrecked_storefront?hmb_source=search_bar). Start game (start.sh).
