I’ve been having the xdg-open issue (LXDE + Chrome) and I have found a workaround that works for me :
I get a message regarding home/foo/lutris:somegame doesn’t exist when I click install in the lutris website, so I went to a shell and typed : lutris somegame. It worked perfectly. Maybe there is a way to transform this lutris:somegame to lutris somegame, but I don’t know how.
Thanx, and I hope this helps for someone else!