this causes an ArrayIndexOutOfBoundsException in XSLTC

Using the following snippet works with XML_SPY, but not with JAXP/XSLTC

I'm trying to gather all @Code Attributes regardless of parentage, and
concatenate with ","...

I am doing this right, aren't I ?

ERROR:
java.lang.ArrayIndexOutOfBoundsException
javax.xml.transform.TransformerException:
java.lang.ArrayIndexOutOfBoundsException at
org.apache.xalan.xsltc.trax.TransformerImpl.transform

<xsl:variable name="errorCode">
        <xsl:for-each select="//@Code">
                <xsl:value-of select="."></xsl:value-of>
                        <xsl:if test="position()!=last()">
                                <xsl:text>, </xsl:text>
                        </xsl:if>
        </xsl:for-each>
</xsl:variable>

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