Answer
The font needs to be installed on whichever machine is actually doing the rendering for that specific report type, which may not be the IFS application server at all: for an operational (Crystal-based) report, that's the server hosting the Crystal Web Services component; for a Quick Report, it's the local workstation running the client. Installing the font only on the IFS application server doesn't help if a different machine is the one generating the output. Whichever machine turns out to be the right one, a reboot of that machine is required after installing the font before the change actually takes effect.