Program: 73974
Project: 73974
Buggy source:
/** 
 * Start the simulation program.
 * @exception IllegalActionException If the simulation process argumentsare invalid.
 */
private void _startSimulation() throws IllegalActionException {
  final String worDir=cutQuotationMarks(workingDirectory.getExpression());
  File commandFile=programName.asFile();
  final String comArg;
  if (commandFile.exists()) {
    comArg=commandFile.toString();
  }
 else {
    commandFile=new File(commandFile.toString() + "String_Node_Str");
    if (commandFile.exists()) {
      comArg=commandFile.toString();
    }
 else {
      comArg=programName.getExpression();
    }
  }
  final String argLin=cutQuotationMarks(programArguments.getExpression());
  List<String> com=new ArrayList<String>();
  com.add(comArg);
  StringTokenizer st=new StringTokenizer(argLin);
  while (st.hasMoreTokens()) {
    com.add(st.nextToken());
  }
  cliPro=new ClientProcess();
  cliPro.redirectErrorStream(true);
  cliPro.setProcessArguments(com,worDir);
  File slf=simulationLogFile.asFile();
  try {
    if (slf.exists()) {
      if (slf.delete()) {
        if (slf.exists()) {
          throw new Exception("String_Node_Str");
        }
      }
    }
    if (!slf.createNewFile()) {
      throw new Exception("String_Node_Str");
    }
    if (!slf.canWrite()) {
      throw new Exception("String_Node_Str");
    }
  }
 catch (  Exception e) {
    String em="String_Node_Str" + LS + "String_Node_Str"+ slf.getAbsolutePath()+ "String_Node_Str"+ LS+ "String_Node_Str"+ this.getFullName()+ "String_Node_Str";
    throw new IllegalActionException(this,e,em);
  }
  cliPro.setSimulationLogFile(slf);
  cliPro.run();
  if (!cliPro.processStarted()) {
    String em="String_Node_Str" + LS + cliPro.getErrorMessage()+ LS+ "String_Node_Str"+ this.getFullName()+ "String_Node_Str";
    throw new IllegalActionException(this,em);
  }
}

Fixed version (ground truth):
/** 
 * Start the simulation program.
 * @exception IllegalActionException If the simulation process argumentsare invalid.
 */
private void _startSimulation() throws IllegalActionException {
  final String worDir=cutQuotationMarks(workingDirectory.getExpression());
  List<String> com=new ArrayList<String>();
  com.add(Simulator.resolveCommandName(programName.asFile()));
  final String argLin=cutQuotationMarks(programArguments.getExpression());
  StringTokenizer st=new StringTokenizer(argLin);
  while (st.hasMoreTokens()) {
    com.add(st.nextToken());
  }
  cliPro=new ClientProcess();
  cliPro.redirectErrorStream(true);
  cliPro.setProcessArguments(com,worDir);
  File slf=simulationLogFile.asFile();
  try {
    if (slf.exists()) {
      if (slf.delete()) {
        if (slf.exists()) {
          throw new Exception("String_Node_Str");
        }
      }
    }
    if (!slf.createNewFile()) {
      throw new Exception("String_Node_Str");
    }
    if (!slf.canWrite()) {
      throw new Exception("String_Node_Str");
    }
  }
 catch (  Exception e) {
    String em="String_Node_Str" + LS + "String_Node_Str"+ slf.getAbsolutePath()+ "String_Node_Str"+ LS+ "String_Node_Str"+ this.getFullName()+ "String_Node_Str";
    throw new IllegalActionException(this,e,em);
  }
  cliPro.setSimulationLogFile(slf);
  cliPro.run();
  if (!cliPro.processStarted()) {
    String em="String_Node_Str" + LS + cliPro.getErrorMessage()+ LS+ "String_Node_Str"+ this.getFullName()+ "String_Node_Str";
    throw new IllegalActionException(this,em);
  }
}