For some reason, it seems that in some servers, SVG and PDF generation from the figures fail.
I presume that it has to do with missing dependencies of "cairo" package (either operating system package dependency, or R package) or similar.
But I'm not sure yet which are the precise packages that need to be installed to solve that issue (we don't have that issue in our own server). Cairo is my first bet.
Joël, can you run this in your server (from a wiki page, if you don't have ssh access to the server where PluginR is installed), and report the output you get?:
You should see something like:
jpeg png tiff tcltk X11 aqua http/ftp sockets libxml fifo cledit iconv TRUE TRUE TRUE TRUE TRUE FALSE TRUE TRUE TRUE TRUE TRUE TRUE NLS profmem cairo TRUE TRUE TRUE
The important part here is the last one, below "cairo", which should say TRUE.