[eluser]Derek Jones[/eluser]
[quote author="Dam1an" date="1240519396"]but if it fails once, it would update the session, and it should work the second time, but it can sometimes take several attempts :S[/quote]
Then it's likely that you are being presented with a cached version of the page with the same "bad" secure hash. There are many service providers that will cache pages for a number of minutes to save their bandwidth costs. It would be extremely tedious, but you could test this by noting your secure hash before submitting, and comparing that to what's used on the subsequent request after a failed submission. Since we're all geeks here:
Code:
$query = $DB->query("SELECT COUNT(*) AS count FROM exp_security_hashes WHERE hash='".$DB->escape_str($_POST['XID'])."' AND ip_address = '".$IN->IP."' AND date > UNIX_TIMESTAMP()-7200");
Phil, I'm not sure exactly what's happening for you, but it's obvious that your work proxy has issues communicating to our network. If you encounter it again, can you do a traceroute to the site?