Dear Experts

am getting the two errors while creating undo tablespace for a new database.

SQL> create undo tablespace undo1 datafile 'C:/oracle/admin/ACER/undo01.dbf' size 512;
create undo tablespace undo1 datafile 'C:/oracle/admin/ACER/undo01.dbf' size 512
*
ERROR at line 1:
ORA-00604: error occurred at recursive SQL level 1
ORA-01655: unable to extend cluster SYS.C_TS# by 3 in tablespace SYSTEM

am not able to understand how to go with this error..
some ppls said
its because of the SYSTEM tablespace(Default). if it is the problem please let me know how ?
please i need u r help