[Xsltforms-support] Rev 628 error using .getInstanceDocument()

SourceForge Headquarters 1320 Columbia Street Suite 310 San Diego, CA 92101 +1 (858) 422-6466

Hi,
I have just moved to rev 628 and some script that had been working fine now
returns the error:
ReferenceError: Can't find variable: XsltForms_context
I am assuming that it is related to the use of .getInstanceDocument() in 
the code. Is my code out-of-date in some way?
Best wishes
Mark
Here is a test form that gives me the error:
<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet href="../xsltforms/xsltforms.xsl" type="text/xsl"?>
<?xsltforms-options debug="yes"?>
<?css-conversion no?>
<html xmlns = "http://www.w3.org/1999/xhtml"
xmlns:xf = "http://www.w3.org/2002/xforms"
xmlns:ev = "http://www.w3.org/2001/xml-events" >

<head>
<title> Test </title>

<script type = "text/javascript" >
<![CDATA[
function getXML() {
var modelElem = document.getElementById("theModel");
xmlDoc = modelElem.getInstanceDocument("content");
}
]]>
</script>
<xf:model id = "theModel" >

<xf:instance id = "content" >
<doc> Hello </doc>
</xf:instance>

<xf:action ev:event = "xforms-ready" >
<xf:load resource = "javascript:getXML()" />
</xf:action>
</xf:model>

</head>
<body>
<p><xf:output ref = "instance('content')" /></p>
</body>
</html>