diff -urNp ./acquia_agent/acquia_agent_streams.inc ../acquia_connector_new/acquia_agent/acquia_agent_streams.inc
--- ./acquia_agent/acquia_agent_streams.inc	2009-06-16 15:18:55.658684356 -0500
+++ ../acquia_connector_new/acquia_agent/acquia_agent_streams.inc	2009-06-16 15:22:39.943888054 -0500
@@ -90,23 +90,7 @@ function acquia_agent_stream_context_cre
  *   The rest of the parameters and return values are the same as xmlrpc().
  */
 function acquia_agent_http_request($context, $url, $headers = array(), $method = 'GET', $data = NULL, $retry = 3) {
-  static $self_test = FALSE;
   $result = new stdClass();
-  // Try to clear the drupal_http_request_fails variable if it's set. We
-  // can't tie this call to any error because there is no surefire way to
-  // tell whether a request has failed, so we add the check to places where
-  // some parsing has failed.
-  if (!$self_test && variable_get('drupal_http_request_fails', FALSE)) {
-    $self_test = TRUE;
-    $works = module_invoke('system', 'check_http_request');
-    $self_test = FALSE;
-    if (!$works) {
-      // Do not bother with further operations if we already know that we
-      // have no chance.
-      $result->error = t("The server can't issue HTTP requests");
-      return $result;
-    }
-  }
 
   // Parse the URL and make sure we can handle the schema.
   $uri = parse_url($url);
@@ -163,9 +147,17 @@ function acquia_agent_http_request($cont
     // host that do not take into account the port number.
     'Host' => "Host: $host",
     'User-Agent' => 'User-Agent: Drupal (+http://drupal.org/)',
-    'Content-Length' => 'Content-Length: '. strlen($data)
   );
 
+  // Only add Content-Length if we actually have any content or if it is a POST
+  // or PUT request. Some non-standard servers get confused by Content-Length in
+  // at least HEAD/GET requests, and Squid always requires Content-Length in
+  // POST/PUT requests.
+  $length = strlen($data);
+  if ($length || $method == 'POST' || $method == 'PUT') {
+    $defaults['Content-Length'] = 'Content-Length: '. $length;
+  }
+
   // If the server url has a user then attempt to use basic authentication
   if (isset($uri['user'])) {
     $defaults['Authorization'] = 'Authorization: Basic '. base64_encode($uri['user'] . (!empty($uri['pass']) ? ":". $uri['pass'] : ''));