It's nothing to do with your version or platform. XMLPARSE
isn't a top level command, it's a function.
regress=> XMLPARSE (CONTENT 'abc<foo>bar</foo><bar>foo</bar>');
ERROR: syntax error at or near "XMLPARSE"
LINE 1: XMLPARSE (CONTENT 'abc<foo>bar</foo><bar>foo</bar>');
^
vs
regress=> SELECT XMLPARSE (CONTENT 'abc<foo>bar</foo><bar>foo</bar>');
xmlparse
---------------------------------
abc<foo>bar</foo><bar>foo</bar>
(1 row)