This happened to me when trying to execute the window app from src4m.zip. After compiling it on 2014 Appliance CS50 (2014-22). First the spl directory was missing form the zip file. The one installed in the appliance seems to be the wrong version or is just not working and it had no Makefile. So I backed it up. I managed to clone the current Stanford version from the git repos and the got a bunch of permission based errors when trying to make spl and make install (yes using sudo). So I updated the Makefile and manually changed some permissions. But even still I got this error when trying to run the app whether I used sudo or not. So I will post the solution below.
I looked at what was happening in the install process and noted that it was creating the spl.jar file but again permissions was the issue. Using sudo didn't make a difference when executing window, so instead I ran these:
sudo chown jharvard:students /usr/local/lib/spl.jar sudo chown jharvard:students /usr/local/lib/libcs.a
Oddly, I have to execute the files from outside the src4m directory. from /usr/local/lib/ I can run sudo ~/Dropbox/src4m/window and it works.