The ImageMagick package and Imagick library are required for PDF Light Viewer plugin to work. Not supported in current context means that the Imagick library is not installed or turned off on the server. To make plugin work you will need to install it or to turn it on.
ImageMagick is the image manipulation library for PHP. ImageMagick is a server software and currently not included into the plugin.
To make it work, someone, you, your server administrator or your hosting provider, should install (or enable, if it’s already installed) this software on your server. If your site is maintained by some administrator, he or she already knows how to install ImageMagick and Imagick libraries. Otherwise the installation could be done through cPanel in some cases and you could try to install it.
Sometimes your hosting provider could restrict installation of additional software. In this case you can contact them for further instructions and details.
To install ImageMagick manually please visit this installation guide.