Introspecting a php file :
<?php

class TestInt{

/**

• // Returns square of given number
• @param string $num
• @return int
  */
  function square1($num) { return $num; }

}

returns the XML as:

<?xml version="1.0" encoding="utf-8"?>
<service-description xmlns="http://ns.adobe.com/flex/service-description/2008"><types><type name="int"/></types><operations><operation name="square1" returnType="int"><argument name="num" type="string"/></operation></operations></service-description>

The XML contains an entry <types><type name="int"/></types> which is wrong as this is a primitive type.