I am trying to write in a file stored in c:\ drive named vin1.txt and getting this error .Please suggest!

> ERROR at line 1: ORA-29280: invalid
> directory path ORA-06512: at
> "SYS.UTL_FILE", line 18 ORA-06512: at
> "SYS.UTL_FILE", line 424 ORA-06512: at
> "SCOTT.SAL_STATUS", line 12 ORA-06512:
> at line 1

HERE is the code

  create or replace procedure sal_status
   (
    p_file_dir IN varchar2,
    p_filename IN varchar2)
     IS  
    v_filehandle utl_file.file_type;
    cursor emp Is
        select * from employees
        order by department_id;
    v_dep_no departments.department_id%TYPE;
     begin
         v_filehandle :=utl_file.fopen(p_file_dir,p_filename,'w');--Opening a file
         utl_file.putf(v_filehandle,'SALARY REPORT :GENERATED ON %s\n',SYSDATE);
         utl_file.new_line(v_filehandle);
         for v_emp_rec IN emp LOOP
            v_dep_no :=v_emp_rec.department_id;
            utl_file.putf(v_filehandle,'employee %s earns:s\n',v_emp_rec.last_name,v_emp_rec.salary);                    
         end loop;
        utl_file.put_line(v_filehandle,'***END OF REPORT***');
        UTL_FILE.fclose(v_filehandle);
     end sal_status;

execute sal_status('C:\','vin1.txt');--Executing