I installed JSON::XS. You're confusing me about which modules you would like installed. Could you please confirm which modules you want installed?
Click "show system installed modules"
I checked that JSON::XS indeed was installed as regular module.
I wanted to check that my site works fine after all, but again failed.
my site is at http://arxiv.heliohost.org/ but it is down! At the same time heliohost.org is online.
Also I can't access it via (s)ftp also.