Thanks spfoonnewb, the snippet I posted was wrong, but that was not the problem.
The problem is that now Godaddy inserts a random string and a random parameter ("rnd" and "nblPLWxHGVnEAfbPcBZp") when searching their auctions page. I hit godaddy.com first (to create the session and store it on the same cookie) but it doesn't work.
Any ideas on how to simulate the behavior they do on the complex Javascripts they run?
$ch = curl_init();
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 2);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE);
curl_setopt($ch, CURLOPT_USERAGENT, "Mozilla/4.0 (compatible; MSIE 5.02; Windows NT 5.0)");
curl_setopt($ch, CURLOPT_COOKIEJAR, dirname(__FILE__).'/godaddycokie.txt');
curl_setopt($ch, CURLOPT_COOKIEFILE, dirname(__FILE__).'/godaddycokie.txt');
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);
curl_setopt($ch, CURLOPT_URL, 'https://auctions.godaddy.com');
curl_exec($ch);
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_POSTFIELDS, 't=16&action=search&hidAdvSearch=ddlAdvKeyword:3|txtKeyword:|ddlCharacters:0|txtCharacters:|txtMinTraffic:|txtMaxTraffic:|txtMinPrice:|txtMaxPrice:|ddlCategories:0|chkAddBuyNow:false|chkAddFeatured:false|chkAddDash:true|chkAddDigit:true|chkAddWeb:false|chkAddAppr:false|chkAddInv:false|ddlPattern1:-|ddlPattern2:-|ddlPattern3:-|ddlPattern4:-|chkSaleOffer:false|chkSalePublic:false|chkSaleExpired:true|chkSaleCloseouts:false|chkSaleUsed:false|chkAddOnSale:false|ddlAdvBids:0|txtBids:|txtAuctionID:|chkTLD1:false|chkTLD2:false|chkTLD3:false|chkTLD4:false|chkTLD5:false|chkTLD6:false|chkTLD7:false|chkTLD233:false|chkTLD240:false|chkTLD251:false|chkTLD292:false|chkTLD69:false|chkTLD22:false|chkTLD85:false|chkTLD396:false|chkTLD51:false|chkTLD50:false|chkTLD465:false|chkTLD466:false|chkTLD80:false|chkTLD366:false|chkTLD62:false|chkTLD205:false|ddlDateOffset:&rpp=15&page=1&pageMode=2&rnd=0.4006484983301911&nblPLWxHGVnEAfbPcBZp=74091bb5e79d499aa8e591b57ed932bb');
curl_setopt($ch, CURLOPT_URL, 'https://auctions.godaddy.com/trpSearchResults.aspx');
$response = curl_exec($ch);
if ($response === false)
{ echo curl_error($ch);}
else
{ echo "Response OK:$response";}