Program: 170001
Project: 170001
Buggy source:
@Override public boolean processCommand(EntityPlayer player,ITerminal terminal,String[] args){
  if (args[0].equalsIgnoreCase("String_Node_Str") && args.length > 1 && args[1] != null && terminal instanceof TPaoTaiZhan) {
    TPaoTaiZhan platform=(TPaoTaiZhan)terminal;
    AccessLevel userAccess=terminal.getUserAccess(player.username);
    if (args[1].equalsIgnoreCase("String_Node_Str")) {
      terminal.addToConsole("String_Node_Str" + platform.getUserAccess(player.username).displayName);
      return true;
    }
 else     if (args[1].equalsIgnoreCase("String_Node_Str") && args.length > 3 && userAccess.ordinal() >= AccessLevel.ADMIN.ordinal()) {
      String username=args[2];
      AccessLevel currentAccess=terminal.getUserAccess(username);
      AccessLevel playerAccess=terminal.getUserAccess(player.username);
      if (playerAccess.ordinal() >= AccessLevel.ADMIN.ordinal()) {
        if (currentAccess != AccessLevel.NONE) {
          AccessLevel newAccess=AccessLevel.get(args[3]);
          if (currentAccess != AccessLevel.OWNER || platform.getUsersWithAcess(AccessLevel.OWNER).size() > 1) {
            if (newAccess != AccessLevel.NONE && terminal.addUserAccess(username,newAccess,true)) {
              terminal.addToConsole(username + "String_Node_Str" + newAccess.displayName);
              platform.worldObj.markBlockForUpdate(platform.xCoord,platform.yCoord,platform.zCoord);
              return true;
            }
          }
        }
      }
 else {
        terminal.addToConsole("String_Node_Str");
        return true;
      }
    }
  }
  return false;
}

Fixed version (ground truth):
@Override public boolean processCommand(EntityPlayer player,ITerminal terminal,String[] args){
  if (args[0].equalsIgnoreCase("String_Node_Str") && args.length > 1 && args[1] != null && terminal instanceof TPaoTaiZhan) {
    TPaoTaiZhan platform=(TPaoTaiZhan)terminal;
    AccessLevel userAccess=terminal.getUserAccess(player.username);
    if (args[1].equalsIgnoreCase("String_Node_Str")) {
      terminal.addToConsole("String_Node_Str" + platform.getUserAccess(player.username).displayName);
      return true;
    }
 else     if (args[1].equalsIgnoreCase("String_Node_Str") && args.length > 3 && userAccess.ordinal() >= AccessLevel.ADMIN.ordinal()) {
      String username=args[2];
      AccessLevel currentAccess=terminal.getUserAccess(username);
      AccessLevel playerAccess=terminal.getUserAccess(player.username);
      if (playerAccess.ordinal() >= AccessLevel.ADMIN.ordinal() && playerAccess.ordinal() >= currentAccess.ordinal() && (!player.username.equalsIgnoreCase(username) || playerAccess == AccessLevel.OWNER)) {
        if (currentAccess != AccessLevel.NONE) {
          AccessLevel newAccess=AccessLevel.get(args[3]);
          if (currentAccess != AccessLevel.OWNER || platform.getUsersWithAcess(AccessLevel.OWNER).size() > 1) {
            if (newAccess != AccessLevel.NONE && terminal.addUserAccess(username,newAccess,true)) {
              terminal.addToConsole(username + "String_Node_Str" + newAccess.displayName);
              platform.worldObj.markBlockForUpdate(platform.xCoord,platform.yCoord,platform.zCoord);
              return true;
            }
          }
        }
      }
 else {
        terminal.addToConsole("String_Node_Str");
        return true;
      }
    }
  }
  return false;
}