Program: 33923
Project: 33923
Buggy source:
/** 
 * Creates the inventory panels from the warp list and adds nav buttons
 */
public void updatePanel(){
  warpPanel.clear();
  Collection<UUID> activeWarps=plugin.getWarpSignsListener().listSortedWarps();
  if (DEBUG)   plugin.getLogger().info("String_Node_Str" + activeWarps.size());
  int panelNumber=activeWarps.size() / (PANELSIZE - 2);
  int remainder=(activeWarps.size() % (PANELSIZE - 2)) + 8 + 2;
  remainder-=(remainder % 9);
  if (DEBUG)   plugin.getLogger().info("String_Node_Str" + panelNumber + "String_Node_Str"+ remainder);
  int i=0;
  for (i=0; i < panelNumber; i++) {
    if (DEBUG)     plugin.getLogger().info("String_Node_Str" + (i + 1));
    warpPanel.add(Bukkit.createInventory(null,PANELSIZE,plugin.myLocale().warpsTitle + "String_Node_Str" + (i + 1)));
  }
  if (DEBUG)   plugin.getLogger().info("String_Node_Str" + (i + 1));
  warpPanel.add(Bukkit.createInventory(null,remainder,plugin.myLocale().warpsTitle + "String_Node_Str" + (i + 1)));
  panelNumber=0;
  int slot=0;
  for (  UUID playerUUID : activeWarps) {
    ItemStack icon=cachedWarps.get(playerUUID);
    if (icon != null) {
      warpPanel.get(panelNumber).setItem(slot++,icon);
      if (slot == PANELSIZE - 2) {
        if (panelNumber > 0) {
          warpPanel.get(panelNumber).setItem(slot++,new CPItem(Material.SIGN,plugin.myLocale().warpsPrevious,"String_Node_Str" + (panelNumber - 1),"String_Node_Str").getItem());
        }
        warpPanel.get(panelNumber).setItem(slot,new CPItem(Material.SIGN,plugin.myLocale().warpsNext,"String_Node_Str" + (panelNumber + 1),"String_Node_Str").getItem());
        panelNumber++;
        slot=0;
      }
    }
  }
  if (remainder != 0 && panelNumber > 0) {
    warpPanel.get(panelNumber).setItem(slot++,new CPItem(Material.SIGN,plugin.myLocale().warpsPrevious,"String_Node_Str" + (panelNumber - 1),"String_Node_Str").getItem());
  }
}

Fixed version (ground truth):
/** 
 * Creates the inventory panels from the warp list and adds nav buttons
 */
public void updatePanel(){
  warpPanel.clear();
  Collection<UUID> activeWarps=plugin.getWarpSignsListener().listSortedWarps();
  if (DEBUG)   plugin.getLogger().info("String_Node_Str" + activeWarps.size());
  int size=activeWarps.size();
  int panelNumber=size / (PANELSIZE - 2);
  int remainder=(size % (PANELSIZE - 2)) + 8 + 2;
  remainder-=(remainder % 9);
  if (DEBUG)   plugin.getLogger().info("String_Node_Str" + panelNumber + "String_Node_Str"+ remainder);
  int i=0;
  for (i=0; i < panelNumber; i++) {
    if (DEBUG)     plugin.getLogger().info("String_Node_Str" + (i + 1));
    warpPanel.add(Bukkit.createInventory(null,PANELSIZE,plugin.myLocale().warpsTitle + "String_Node_Str" + (i + 1)));
  }
  if (DEBUG)   plugin.getLogger().info("String_Node_Str" + (i + 1));
  warpPanel.add(Bukkit.createInventory(null,remainder,plugin.myLocale().warpsTitle + "String_Node_Str" + (i + 1)));
  panelNumber=0;
  int slot=0;
  for (  UUID playerUUID : activeWarps) {
    ItemStack icon=cachedWarps.get(playerUUID);
    if (icon != null) {
      warpPanel.get(panelNumber).setItem(slot++,icon);
      if (slot == PANELSIZE - 2) {
        if (panelNumber > 0) {
          warpPanel.get(panelNumber).setItem(slot++,new CPItem(Material.SIGN,plugin.myLocale().warpsPrevious,"String_Node_Str" + (panelNumber - 1),"String_Node_Str").getItem());
        }
        warpPanel.get(panelNumber).setItem(slot,new CPItem(Material.SIGN,plugin.myLocale().warpsNext,"String_Node_Str" + (panelNumber + 1),"String_Node_Str").getItem());
        panelNumber++;
        slot=0;
      }
    }
  }
  if (remainder != 0 && panelNumber > 0) {
    warpPanel.get(panelNumber).setItem(slot++,new CPItem(Material.SIGN,plugin.myLocale().warpsPrevious,"String_Node_Str" + (panelNumber - 1),"String_Node_Str").getItem());
  }
}