If anyone was encountering a pthread error when trying to run the JA++ mod on a Linux OpenJK server, make sure your .sh script that runs the server looks similar to this: LD_PRELOAD=/lib/x86_64-linux-gnu/libpthread.so.0 ./openjkded.x86_64 +set fs_homepath ./ +set fs_game "japlus" +exec server.cfg The biggest thing to note is the LD_PRELOAD prefix. Note that this is particularly for a Linux 64-bit OpenJK server.