I couldn't find the reason for this behavior. In the log, I found:
HTML Code:
19.11.2008 - 12:00:16 => DEBUG - Endereço de e-mail duplicado.<br><br><br> <a href='../../isp_manager/frame_start.php?'>Next >></a>
19.11.2008 - 12:02:51 => - Setting Signalfile Failed: insert
19.11.2008 - 12:04:22 => - Setting Signalfile Failed: insert
19.11.2008 - 12:05:23 => - Setting Signalfile Failed: insert
19.11.2008 - 12:06:36 => - Setting Signalfile Failed: insert
19.11.2008 - 12:09:28 => - Setting Signalfile Failed: insert
19.11.2008 - 12:10:19 => - Setting Signalfile Failed: update
19.11.2008 - 13:36:24 => - Setting Signalfile Failed: insert
19.11.2008 - 13:36:46 => - Setting Signalfile Failed: insert
19.11.2008 - 13:37:08 => - Setting Signalfile Failed: insert
19.11.2008 - 13:37:27 => - Setting Signalfile Failed: insert
19.11.2008 - 13:37:44 => - Setting Signalfile Failed: insert
19.11.2008 - 13:38:00 => - Setting Signalfile Failed: insert
19.11.2008 - 13:38:22 => - Setting Signalfile Failed: insert
19.11.2008 - 13:38:46 => - Setting Signalfile Failed: insert
19.11.2008 - 13:39:06 => - Setting Signalfile Failed: insert
19.11.2008 - 13:40:50 => - Setting Signalfile Failed: insert
19.11.2008 - 13:42:35 => - Setting Signalfile Failed: insert
19.11.2008 - 13:42:53 => - Setting Signalfile Failed: insert
19.11.2008 - 13:43:18 => - Setting Signalfile Failed: insert
19.11.2008 - 13:44:56 => - Setting Signalfile Failed: insert
19.11.2008 - 13:45:15 => - Setting Signalfile Failed: empty trash
19.11.2008 - 13:46:55 => - Setting Signalfile Failed: empty trash
19.11.2008 - 13:47:37 => - Setting Signalfile Failed: insert
19.11.2008 - 13:48:00 => - Setting Signalfile Failed: insert
19.11.2008 - 13:48:11 => - Setting Signalfile Failed: empty trash
19.11.2008 - 13:52:04 => - Setting Signalfile Failed: insert
19.11.2008 - 13:52:58 => - Setting Signalfile Failed: insert
19.11.2008 - 13:53:12 => - Setting Signalfile Failed: empty trash
19.11.2008 - 13:53:54 => DEBUG - The name www.digiscrappersbrasil.com.br is already in use by another site or domain.<br><br><br> <a href='../../isp_manager/frame_start.php?'>Next >></a>
19.11.2008 - 14:02:15 => - Setting Signalfile Failed: delete: do
19.11.2008 - 14:02:47 => - Setting Signalfile Failed: insert
19.11.2008 - 14:05:40 => - Setting Signalfile Failed: update
19.11.2008 - 17:49:42 => INFO - /root/ispconfig/scripts/lib/classes/ispconfig_system.lib.php, Line 728: /etc/init.d/apache2 restart &> /dev/null
But for the timestamps, all I can see is that happened several errors, but I'm still clueless about where to look for it.
BTW, the first line is in Portuguese, and means "Email address is duplicated".
Thanks for your help