IO-error -2 at ... : Under linux you can get this message at compiler startup. It means typically that the compiler doesn’t find the error definitions file. You can correct this mistake with the -Fr (see page 109) option under linux.
Error : File not found : xxx or Error: couldn’t compile unit xxx: This typically happens when your unit path isn’t set correctly. Remember that the compiler looks for units only in the current directory, and in the directory where the compiler itself is. If you want it to look somewhere else too, you must explicitly tell it to do so using the -Fu (see page 109) option. Or you must set up a configuration file.