Is this a valid expression?

Hello list,

I'm using XSL to transform a XML file to another XML file.

My XSL script contains this line:

<xsl:apply-templates select="/export//*[(not(parent::Zubehoer)) AND
(not(parent::Ersatzteile))]/Produktobjekt" mode="article"/>

What I want is 'every Produktobjekt that doesn't have a Zubehoer or a
Ersatzteile as parent'. For me, the line seems correct, but that doesn't
mean a thing.

I am using Saxon 6.4.

Saxon barfs at my script on this line with the error message

Error on line xxx of (my XSL file):
  Error in expression /export//*[(not(parent::Zubehoer)) AND
(not(parent::Ersatzteile))]/Produktobjekt: expected "]", found "<function>"

(Which is the line above)

What am I doing wrong? Please, dear list, show me the error of my ways!

Greetings,
Christian Caesar

 XSL-List info and archive:  http://www.mulberrytech.com/xsl/xsl-list