Why does heredoc fail in this instance?

Hi If I use $snippet = ""; and escape the quotes in the block then it works. But if I use it as is below, it fails with no useful error message. Why? Thanks, Peter function GetAddCommentSnippet($args) { $topic_id = $args[id]; $return_page = $args[return_page]; $snippet = <<<EOS <form action="$this->this_cgi" method="post"> <br>Your First Name: <input type="text" name="FirstName" value=""> <br>Your Last Name: <input type="text" name="LastName" value=""> <br>Your Email Address: <input type="text" name="EmailAddress" value=""> <br>Your Comments: <br> <textarea cols="40" rows="4" name="Comments"></textarea> <br> <input type="submit" value="submit now"> <input type="hidden" name="action" value="AddComment"> <input type="hidden" name="response_to_id" value="$topic_id"> <input type="hidden" name="r" value="$return_page"> </form> EOS; return $snippet; } // END GetAddCommentSnippet --------------------------- "Reality is that which, when you stop believing in it, doesn't go away". -- Philip K. Dick