Really, really good thinking to put that into a PHP script. Also, funny that your host doesn't give you SSH access, but does allow you to run shell_exec. Some hosts... :\
Anyway, most likely your host is firewalling you. Some hosts will firewall outbound connections from PHP scripts, some will prevent you from even attempting to make an outbound connection from a PHP script. That sort of host, generally, isn't going to work well with Magento.
I'd contact your hosting provider and ask them if they have some sort of firewall on outbound requests, or if they're preventing certain PHP functions like file_get_contents from connecting to remote servers.
PEAR's downloadHttp function, which is most likely what is returning that error, uses the function fsockopen which uses sockets. It's possible that your host has disabled support for sockets or you're running on an odd server configuration that PHP can't use sockets on.
If your host says they aren't blocking anything, the next step would be to write a PHP file that attempts to open a connection using fsockopen and testing that. Something like this:
<?php
$fp = fsockopen("www.example.com", 80, $errno, $errstr, 30);
if (!$fp) {
echo "$errstr ($errno)<br />\n";
} else {
echo "Connected successfully!<br />\n";
}
?>
If that fails, then you know it's not a problem with Magento or Magento Connect, it's a problem with your host.
--Joshua Warren - @JoshuaSWarren on Twitter
CEO,
Creatuity
