difference between nameofelement and (nameofelement)

Hi,

what is the difference between "nameofelement" and
"(nameofelement)" in XSL?

The line

<xsl:with-param name="number"
   select="preceding::footnote/preceding::endnote" />

works with Saxonb 8 and Xalan 2.6.0, whereas

<xsl:with-param name="number"
   select="(preceding::footnote)/(preceding::endnote)" />

works with Saxon but gives the following error in Xalan:

"Relative location path expected following '/' or '//'"

Hope this is not a Xalan-specific question. :)

Thanks - Burghard

ps: Of course the given line is a reduced version. The
    full version is:

count( (preceding::footnote[(_at_)start] |
preceding::endnote[(_at_)start])[position()=last()]/(preceding::footnote |
preceding::endnote))