// relative URI into an absolute URI.
XObject arg2 = arg1Expr.execute(xctxt);
if (XObject.CLASS_NODESET == arg2.getType())
{
int baseNode = arg2.iter().nextNode();
if (baseNode == DTM.NULL)
{
// See http://www.w3.org/1999/11/REC-xslt-19991116-errata#E14.
// If the second argument is an empty nodeset, this is an error.