In XSLT 1.0 you can't use a function call on the rhs of "/". You need to use
xsl:for-each to set the context node for id():

<xsl:for-each select="document(..)">
   <xsl:if test="id($jid) = 'footnote'>...

Michael Kay
http://www.saxonica.com/ 

> -----Original Message-----
> From: Trevor Nicholls [mailto:trevor@xxxxxxxxxxxxxxxxxx] 
> Sent: 19 October 2007 17:56
> To: xsl-list@xxxxxxxxxxxxxxxxxxxxxx
> Subject:  error testing id() in external document
> 
> 
> Using xsltproc (libxml), and thus inside an <xsl:stylesheet 
> version="1.0">, the following template generates an error:
> 
>   <xsl:template match="jump[@srcfile]">
>    <xsl:variable name="jfil" 
> select="substring-before(@srcfile,'#')" />
>    <xsl:variable name="jid" select="substring-after(@srcfile,'#')" />
>    <!-- footnotes are an invalid external reference -->
>    <xsl:if test="local-name(document($jfil,/)/id($jid)) = 'footnote'">
>     <xsl:message terminate="yes">
>      <xsl:text>Footnote reference to external document (</xsl:text>
>      <xsl:value-of select="@srcfile" />
>      <xsl:text> found in </xsl:text>
>      <xsl:value-of select="$myfullself" />
>     </xsl:message>
>    </xsl:if>
>   </xsl:template>
> 
> The error is:
> 
>   XPath error : Invalid expression
>   xsl:if : could not compile test expression 'local-name(.. etc.
> 
> Is that really an invalid expression? Is there a valid 
> expression that will achieve the same thing?
> 
> Thanks
> Trevor