Help. Strange behavior with imap, php and apache

I just installed Red Hat 7.3 with Apache and PHP. I ran a simple script to test the imap_open function and it doesn't work when using the values for my server. http://www.gym.itesm.mx/imap.php However, if the mailbox I request to open is on another server, it does work. The strange thing is that a friend of mine has the same script running on his server (http://pollux.icon.net.mx/~antonio/imap.php) and he can read a mailbox from my server as well as any other. When I run the script on my server and try to access a local mailbox I get the following error: Warning: Couldn't open stream {www.gym.itesm.mx:143}INBOX in /home/campus/html/imap.php on line 5 I just don't know what could be wrong. Help is appreciated. Here is the script: <?php function test_imap($mbx,$uid,$pwd) { if (!$mbox = imap_open ($mbx, $uid, $pwd)) { echo "<br /><br />"; echo "<span style='font size: x-large;color:red;'>Password incorrecto</span>"; echo "<br /><br />"; echo "<pre>"; echo "<b>Mailbox.:</b> $mbx<br />"; echo "<b>Cuenta..:</b> $uid<br />"; echo "<b>Password:</b> $pwd<br />"; echo "<b>Error...:</b> "; echo imap_last_error(); echo "</pre>"; } else { echo "Password correcto: $mbx"; imap_close($mbox); } } if (!isset($mbx1)) $mbx1 = "{www.gym.itesm.mx:143}INBOX"; if (!isset($uid1)) $uid1 = "gsoberon"; if (!isset($pwd1)) $pwd1 = "mypass"; if (isset($test)) { test_imap($mbx1,$uid1,$pwd1); } ?> <html> <body> <hr> <form action="imap.php" method="get"> <p> mailbox: <input type=text name=mbx1 value="<?echo $mbx1;?>"><br /> usuario: <input type=text name=uid1 value="<?echo $uid1;?>"><br /> passwd: <input type=text name=pwd1 value="<?echo $pwd1;?>"><br /> <br /> <input type=submit name="test" value="Test"> </p> </form> </body> </html> -- Sergio T.