Problem with Squirrelmail talking to Courier-IMAP on another server

I followed this guide [Virtual Users And Domains With Postfix, Courier, MySQL And SquirrelMail (CentOS 5.3 x86_64)] available at http://www.howtoforge.com/virtual-us...tos-5.3-x86_64

I set up this mail server on 10.10.0.200. I have a production webserver on 10.10.0.54. The gateway for both these servers is at 10.10.0.51. Above this gateway in the hierarchy is a firewall. All the traffic, be it http or smtp, that arrive at the external ip is forwarded to the webserver at 10.10.0.54.

After I set up the mail server, i was able to send out email, but not receive. Of course, because port 25 packets weren't reaching the email server. So I fixed this problem by using iptables prerouting and postrouting commands on the webserver. Basically I forwarded I port 25 packets arriving at the webserver to the email server. Now I can receive mails as well.

Now my squirrelmail is installed on the mailserver as well. How to access this from the outside world? There are websites being served from the webserver at 10.10.0.54, so I can't just forward port 80 to the email server. I was thinking to install squirrelmail on the webserver (10.10.0.54) and make it talk to courier-imap on the email server (10.10.0.200).

So I installed squirrelmail on the 10.10.0.54 webserver and edited /etc/squirrelmail/config.php and made the following changes.

$domain = 'localhost';
$imapServerAddress = '10.10.0.200';
$imapPort = 143;
$useSendmail = true;
$smtpServerAddress = '10.10.0.200';
$smtpPort = 25;
$sendmail_path = '/usr/sbin/sendmail';
$sendmail_args = '-i -t';
$pop_before_smtp = false;
$imap_server_type = 'courier';
$invert_time = false;
$optional_delimiter = '.';

Now, when I login to the squirrelmail web interface, I get a blank screen. Anything that I am missing? Any other setting that I need to change?

Also, I have websites being hosted for four domains on my webserver. I want all of them to access their mail by going to mail.theirdomain.com. By default, squirrelmail is accessed by going to www.theirdomain.com/webmail.
I probably can set up a subdomain using apache virtual host directive. but i will need to change some setting in squirrelmail.conf under /etc/httpd/conf/cquirrelmail.conf. what would that be?

I tried to debug the blank white screen that I am getting. These are my logs:

On the mail server (10.10.0.200) (/var/log/maillog)

Mar 12 16:51:27 mail1 imapd: Connection, ip=[::ffff:10.10.0.54]
Mar 12 16:51:27 mail1 imapd: LOGIN, user=user@domain.ca, ip=[::ffff:10.10.0.54], port=[53566], protocol=IMAP
Mar 12 16:51:27 mail1 imapd: LOGOUT, user=user@domain.ca, ip=[::ffff:10.10.0.54], headers=0, body=0, rcvd=30, sent=238, time=0

On the webserver (10.10.0.54), I get the following in apache logs

[Sat Mar 13 20:13:50 2010] [error] [client 99.244.21*.***] File does not exist: /var/www/html/domain/favicon.ico
[Sat Mar 13 20:13:53 2010] [error] [client 99.244.21*.***] File does not exist: /var/www/html/domain/favicon.ico

I've turned on error reporting in php.ini, but all is get is a blank page

display_errors = On
error_reporting = E_ALL

I thank you all in advance for all ur help.