Hi

The error you get is because your syntax is wrong...Check this out...for your error message
http://technet.oracle.com/docs/produ...00.htm#1003914

Do the following...IF YOU DON'T WANT THE CONTENTS OF THE DATAFILE YOU HAVE LOST to create a new tablespace

1. drop the tablespace.
Code:
drop tablespace (give_tablespace_name) including contents;
2. create new tablespace.
Code:
create tablespace (give_tablespace_name) datafile 'G:\Oracle\oradata\mydb\users01.dbf' size 20m
extent management local
uniform size 64k;
HTH.