psqlexception syntax error at or near "$"

In attempting to execute ddl that will create functions I am getting errors which will not allow the functions to be created.  In running with the 8.4 driver if I attempt the following:

CREATE OR REPLACE FUNCTION system_info_fnc01() RETURNS trigger AS
$$
declare
  iCnt       integer;
begin
  select count(*) into  iCnt from  system_info;
  if ( iCnt > 0 ) then
     raise exception ''System Info record already present'';
  end if;
  return new;
end;
$$
LANGUAGE 'plpgsql' IMMUTABLE

I get an error with the $$.  In substituting an ' for $$ the following occurs:
unterminated quoted string at or near "' declare iCnt integer"

If I then set the delimiter to something like '|' I still get the unterminated quote string problem. Could someone tell me how to get around this problem?

Thanks