Have you tried fetching that page on the production server from the command line with (for example) wget?
If you cannot fetch pages from that host at all, it's possible that your network administrator has configured a block on outgoing http requests, or the sysadmin has made a config error.
Try it from the command line first, and if that works, maybe PHP is at fault. But if you can't do it from the shell, forget it.
Mark