Problem with readfile, fsockopen, intermittent with apache

Hi all, I've been having a problem with readfile and fsockopen not working all the time with my PHP installation. The code worked fine for months without and then suddenly stopped working. The errors getting from the respective calls are: Warning: readfile(http://www.someurl.com?arg) http://www.php.net/function.readfile failed to create stream: HTTP request failed! and: fsockopen() [function.fsockopen]: php_hostconnect: connect failed The strange thing about both of these errors, is that once the error is occuring and the functions are not working, if I restart Apache (php is running as an apache module), then the functions will work for a short time (havn't figured out exactly how long, at least 30 minutes or an hour) before something happens and they stop working again with the above errors. I'm not certain it is a PHP issue, but may be something else that PHP interacts with. I'm very stumped due to the odd behavior when restarting apache. Thanks for any help, Steven