Warning: implode() [function.implode]: Invalid arguments passed

Quando clico na segunda página, por exemplo, dá isso: Warning: implode() [function.implode]: Invalid arguments passed

É essa linha:

$links2 = implode(" | ", $links);

Esté é o código da minha galeria de imagens com paginação:

<?

$qSettings = "select * from `settings` where `ID` = '1'";
$rSettings = mysql_query($qSettings) or die(mysql_error());
$aSettings = mysql_fetch_array($rSettings);

echo "<center>";

if(!empty($_GET[start]))

{

$Start = $_GET[start];
}

else {

$Start = '0';
}

$ByPage = $aSettings[Columns_per_Page] * $aSettings[Rows_per_Page];

$qnav = "select * from `images` where `Username` = '$_SESSION[username]' and `Published` = 'Yes' Order by `ImageID` DESC";
$rnav = mysql_query($qnav) or die(mysql_error());
$rows = mysql_num_rows($rnav);

if($rows > $ByPage)

{

$NextPrev = "<br><table align=center width=50%>";
$NextPrev .= PAGINACAO . ': | ';

$pages = ceil($rows/$ByPage);

$pagesLimit = 5;//Limite de páginas

$lowAllow = (int)($Start - ($pagesLimit / 2));
$start = ($lowAllow <= 0) ? 1 : $lowAllow;
$aboveAllow = $start + $pagesLimit;
$until = ($aboveAllow > $pages) ? $pages : $aboveAllow;

for($i = $start; $i <= $until; $i++)

{

$PageStart = $ByPage*$i;

$i2 = $i + 1;

if($PageStart == $Start)

{

$links[] = "$i2\n\t ";
}

elseif($PageStart < $rows) {

$links[] = " <a href=\"myimages.php?Start=$PageStart&ByPage=$ByPage\">$i2</a>\n\t ";
}
}

$links2 = implode(" | ", $links);

$NextPrev .= "$links2";

$NextPrev .= " | </td>";

$NextPrev .= "</table>\n";

}

echo "<center>$NextPrev</center>";
$WidthHeight = explode(" x ","$aSettings[Popup_window]");

$qData = "select * from `images` where `Username` = '$_SESSION[username]' and `Published` = 'Yes' order by `ImageID` DESC limit $Start, $ByPage";
$rData = mysql_query($qData) or die(mysql_error());
$Total = mysql_num_rows($rData);

if(mysql_num_rows($rData) == '0') {

?>

<center style='background: #FCC; color: #A00; font-size: 1.3em; padding: 7px;'><?=AINDA_NAO_POSSUI?></center>

<?
}
else
{

echo '<table border="0" cellspacing="'.$aSettings[space_between_thumbs].'" width="750">
';

$n = 1;

while($aData = mysql_fetch_array($rData))
{

$b = $n%$aSettings[Columns_per_Page];

if($aSettings[show_full_sized_image]==Yes)

{

$image = "<a href=\"#\" onclick=\"javascript:window.open('popup.php?id=$aData[image]', '_blank', 'width=$WidthHeight[0], height=$WidthHeight[1], scrollbars=yes');return false\"><img border=\"0\" src=\"images_files/redimensionar.php?arquivo=$aData[image]&largura=200&altura=200\"></a>";
}

else
{

$image = "<a href=\"myimages.php?Cid=$_GET[Cid]&SubID=$_GET[subID]&ImageView=$aData[image]\"><img border=\"0\" src=\"images_files/redimensionar.php?arquivo=$aData[image]&largura=200&altura=200\"></a>";
}

if($aSettings[Display_File_name]=="Yes")

{

$Title = "<br>$aData[Title]";
}

if($b == 1)

{

echo "<tr>\n";
}

/ menu de opções exibido abaixo da imagem /

echo "<td><center>$image $Title <br><a href=\"deleteimage.php?ImageID=$aData[imageID]\" onclick=\"return confirmLink(this, 'Tem certeza?')\"><img src='http://www.theimageup.com/icones/excluir.png' border='0' alt='Excluir Imagem' title='Excluir Imagem'/></a> <a target=_blank href=\"http://www.pixlr.com/editor/?image=http://www.theimageup.com/images_files/$aData[image]&loc=pt-br\"><img src='http://www.theimageup.com/icones/editar.png' border='0' alt='Editar Imagem' title='Editar Imagem'/></a></center></td>\n";

if($b == 0)

{

echo "</tr>\n\n";
}

elseif($Total == $n)
{

echo "</tr>\n\n";
}

$n++;
}

echo'</table>';

echo'</center>';

}

?>

O que tem de errado, amigos?