The next command should not even work on a corefile process, and checks should be placed to prohibit use. Current usage: [pmuldoon@localhost frysk_bin]$ ./frysk-core/frysk/bindir/fhpd core.11108 Attached to core file: /home/pmuldoon/frysk_bin/core.11108 (fhpd) next Internal Error: java.lang.NullPointerException at frysk.stepping.SteppingEngine.stepOver(fhpd) at frysk.hpd.StepNextCommand.interpret(fhpd) at frysk.hpd.ParameterizedCommand.interpret(fhpd) at frysk.hpd.MultiLevelCommand.interpret(fhpd) at frysk.hpd.CLI.execCommand(fhpd) at frysk.bindir.fhpd.main(fhpd)