Warning:bad arguments to implode

[wvmlt]

I get the following warning whenever I go on the admin side and look at who's online:

 

 

Warning: Bad arguments to implode() in /home/virtual/site55/fst/var/www/html/catalog/admin/whos_online.php on line 107

 

 

Here is the script:

 

 

 

<td class="dataTableContent"><?php echo gmdate('H:i:s', $time_online); ?></td>

<td class="dataTableContent" align="center"><?php echo $whos_online['customer_id']; ?></td>

<td class="dataTableContent"><?php echo $whos_online['full_name']; ?></td>

<td class="dataTableContent" align="center"><?php echo $whos_online['ip_address']; ?></td>

<td class="dataTableContent"><?php echo date('H:i:s', $whos_online['time_entry']); ?></td>

<td class="dataTableContent" align="center"><?php echo date('H:i:s', $whos_online['time_last_click']); ?></td>

<td class="dataTableContent"><?php if (eregi('^(.*)' . tep_session_name() . '=[a-f,0-9]+[&]*(.*)', $whos_online['last_page_url'], $array)) { echo $array[1] . $array[2]; } else { echo $whos_online['last_page_url']; } ?> </td>

</tr>

 

 

 

This is the line it says is bad:

 

else { echo $whos_online['last_page_url']; } ?> </td>

 

It's the last line in the above portion of the script