Re: Placing mark-up in between strings

   A sequence of more than one item is not allowed
        as the first argument of ati:replace-with-nodes() 

You have

    if ( exists($words-to-replace) ) then
              ati:replace-with-nodes(
                  ati:replace-with-nodes-1(

so teh first argument to replace-with-nodes is generated by
ati:replace-with-nodes-1 but that does not return a single string but a
sequence of nodes
      <xsl:function name="ati:replace-with-nodes-1" as="node()*">
                                                        ^^^^^^^^^

David