Linux NW.JS build not working

Someone who bought my game recently told me that launching the game gave him this error:

./fragilesoftmachines[6108:0430/224646:ERROR:browser_main_loop.cc(170)] Running without the SUID sandbox! See https://code.google.com/p/chromium/wiki/LinuxSUIDSandboxDevelopment for more information on developing with the sandbox on.
LaunchProcess: failed to execvp:
/home/rick/Spiele/fragilesoftmachines_linux64/fragilesoftmachines
LaunchProcess: failed to execvp:
/proc/self/exe
[6108:0430/224646:ERROR:child_process_launcher.cc(479)] Failed to launch child process
[6108:0430/224646:ERROR:child_process_launcher.cc(479)] Failed to launch child process
[6108:0430/224646:ERROR:channel.cc(305)] RawChannel read error (connection broken)[/code:1o9nafsm]

He says he is running Linux Mint 15, and downloaded the correct bit-version of the game (64bit).
I do not have a machine running Linux, nor do I know proper code or can tell what is going on.  Could someone explain why he is getting this error and how I can help him solve this? 
Thank you!

I made a quick tutorial for Linux export here if it can help you. Mainly works for Ubuntu based distribs, but maybe you'll find something interesting?

http://www.scirra.com/forum/how-to-node ... =linux+mac

That said, you really should have at least one linux distrib running on one of your computers (dual boot or virtual machine) to check if your game runs ok. Selling stuff you can't test by yourself is a super risky business.

(I dare to write this because I also took a long time before installing Linux myself. I'm absolutely not a Linux guy, but quickly realized it was mandatory to sell games on Linux.)

Hm... I'm not sure your solution is the solution to the problem I'm having?

You seem to be solving the problem of "games don't load if there's too many files because the current build of NW.JS is dumb" and I'm not sure that's the problem I'm having. My game is relatively light, and this is the first time someone's had a problem with this Linux build (and expressed it to me anyway).

This problem seems to be with a missing Chromium package? I'm honestly not sure, I don't know what the error message means, and I don't understand why something would be outright missing.

I know I *should* have a computer running any OS I plan on distributing for, and I know I especially don't have an excuse for not having Linux, but I honestly don't have a good enough understanding of computers in general to know what I'm getting into. I may look into getting my laptop to dual-boot, because it's already got half a foot in the grave and I won't be devastated if I mess something up. I just know I'm going to break something. heh...

You could try older versions of nwjs, but this sounds more like an issue with permissions on the machine.

Yes, it's not directly related, but I thought the parts about dropbox/google drive or "allow the game to run as an app once on a linux system" could help.

Especially when I read you don't have a Linux system to test on.