Stumped on PlPgSql

Ok, I give up :-(

I have recently upgraded my development system to 7.0.2, my production server is still
6.5.1

I have a Plpsgsql function that I have been using in 6.5.1 and it works fine.

The same function on 7.0.2 gives me an error. I have looked in the doc and haven't
seen any change in syntax but maybe Im blind.

The function is

-- ------------------------------------------------------------------------
-- PostCharge
-- ------------------------------------------------------------------------
CREATE FUNCTION "postcharge" ( int4, int4, int4, int4, int4, text )
   RETURNS bool AS '
   DECLARE
      clnt ALIAS FOR $1;
      invnum ALIAS FOR $2;
      rescode ALIAS FOR $3;
      zone ALIAS FOR $4;
      q ALIAS FOR $5;
      cmmnt ALIAS FOR $6;
      res RECORD;
      ctrl RECORD;
      amt float8;
      qf float8;
   BEGIN
      SELECT * INTO res FROM resource WHERE code = rescode;
      IF res.status <> ''A'' THEN
         RETURN ''f'';
      END IF;
      SELECT * INTO ctrl FROM control;
      qf := float8( q );
      IF zone = 0 THEN
         amt := res.rate_internal * qf;
      END IF;
      IF zone = 1 THEN
         amt := res.rate_local * qf;
      END IF;
      IF zone = 2 THEN
         amt := res.rate_national * qf;
      END IF;
      IF zone = 3 THEN
         amt := res.rate_international * qf;
      END IF;
      INSERT INTO client_trans (
         client, resource, invnum, period, tstamp, comment, qty, amount
      ) VALUES (
         clnt, rescode, invnum, ctrl.open_period, ''now'', cmmnt, q, amt );
      RETURN ''t'';
   END;
' LANGUAGE 'plpgsql';

The error is

ERROR:  parser: parse error at or near "$1"


Any help would be appreciated.