I have the same issue here.
In my situation the link is shown as: "
http://www.gargoyle-router.com/packages ... xx/default".
With that I'm not able to f.e. install the german language plugin.
PS: using the "gargoyle_1.9.x-ar71xx-generic-tl-wr841n-v9-squashfs-sysupgrade.bin" from the "gargoyle-ispy 2016-April-08 07_55.torrent".
Update: Also plugins which could be installed because of small size (like the "Theme by Matei for Gargoyle, Version: 1.9.0-1, Status: Not Installed
Required Disk Space: 7.285 kBytes" can't be installed. This means, I can install it, but even after a reboot nothing changes. The plugin keeps installable.