When launching the latest IDJC, it will show the profile selection window. However, upon selecting a profile, it will crash with the following error message.
jack client ID: idjc_default
something bad happened
The profile selection window runs prior to launching the back end.
You probably didn't run ldconfig after installing libshout-idjc or the install location (/usr/local/lib) isn't listed in /etc/ld.conf.
Following the install instructions at idjc.sf.net (or the doc directory) will ensure this isn't an issue.
Running from Virtual Box I had to start jackd manually beforehand with
$ jackd -t 100 -d alsa -r 44100 -p 2048 -n 3
I expect something is not fully linked and the following command will probably indicate what that something is.
Assuming you installed it in /usr/lib and not /usr/local/lib
$ ldd -r /usr/lib/idjc.so
> You probably didn't run ldconfig after installing libshout-idjc...
Okay, I'm officially an idiot now. Forget I said anything.