Thank you.
Unfortunately, even re-installation didn't work. Thus I checked the error logs and I found these:
"[Sat Jul 23 00:26:30 2011] [error] [client 194.225.53.5] File does not exist: /home/jivresea/public_html/404.shtml
[Sat Jul 23 00:26:30 2011] [error] [client 194.225.53.5] File does not exist: /home/jivresea/public_html/jivr/favicon.ico
[Sat Jul 23 00:23:54 2011] [error] [client 194.225.53.5] File does not exist: /home/jivresea/public_html/404.shtml, referer:
http://www.jivresearch.org/lemon/install.php[Sat Jul 23 00:23:54 2011] [error] [client 194.225.53.5] File does not exist: /home/jivresea/public_html/lemon8, referer:
http://www.jivresearch.org/lemon/install.php[Sat Jul 23 00:23:02 2011] [error] [client 194.225.53.5] File does not exist: /home/jivresea/public_html/404.shtml
[Sat Jul 23 00:05:24 2011] [error] [client 157.55.16.57] File does not exist: /home/jivresea/public_html/robots.txt"
I am not sure if these can help to find the problem.
I would be grateful if you can help.
Regards,
Omid