--- Zend/Amf/Parse/Amf3/Serializer.orig.php	2010-06-03 09:34:49.000000000 -0500
+++ Zend/Amf/Parse/Amf3/Serializer.php	2010-06-03 09:36:46.000000000 -0500
@@ -224,33 +224,33 @@
 
     /**
      * Send string to output stream
      *
      * @param  string $string
      * @return Zend_Amf_Parse_Amf3_Serializer
      */
     public function writeString(&$string)
     {
         $len = strlen($string);
         if(!$len){
             $this->writeInteger(0x01);
             return $this;
         }
 
-        $ref = array_search($string, $this->_referenceStrings, true);
-        if($ref === false){
-            $this->_referenceStrings[] = $string;
+        $ref = array_key_exists($string, $this->_referenceStrings) ? $this->_referenceStrings[$string] : false;
+        if ($ref === false){
+            $this->_referenceStrings[$string] = count($this->_referenceStrings);
             $this->writeBinaryString($string);
         } else {
             $ref <<= 1;
             $this->writeInteger($ref);
         }
 
         return $this;
     }
 
     /**
      * Send ByteArray to output stream
      *
      * @param  string|Zend_Amf_Value_ByteArray  $data
      * @return Zend_Amf_Parse_Amf3_Serializer
      */