Syntax Error in COPY when “create function”

Am I forgetting some limitation? 

I get " ERROR: syntax error at or near "$1"

SQL state: 42601 "with this

CREATE FUNCTION Import1() RETURNS text AS $$

DECLARE

            path Char(100);

BEGIN

            path = 'C:/zhl/hjs/anc_area.att';

            COPY anc_areaAtt FROM path CVS;

            RETURN path;

END;

$$ LANGUAGE plpgsql;

SELECT  Import1() ;

CREATE FUNCTION Import2() RETURNS text AS $$

DECLARE

            path Char(100);

BEGIN

            COPY anc_areaAtt FROM 'C:/zhl/hjs/anc_area.att' CSV;

            return path;

END;

$$ LANGUAGE plpgsql;

SELECT  Import2() ;

Does this mean the "filename" in COPY command can not be a variable?

By the way, my OS is windowXP.