Yep, my default nls_date_format is 'dd.mm.rr', so i tried other way around:
Code:
SQL> select * from v$version;

BANNER
----------------------------------------------------------------
Oracle8i Enterprise Edition Release 8.1.7.2.0 - Production
PL/SQL Release 8.1.7.2.0 - Production
CORE    8.1.7.0.0       Production
TNS for Solaris: Version 8.1.7.2.0 - Production
NLSRTL Version 3.4.1.0.0 - Production

SQL> select * from NLS_SESSION_PARAMETERS where PARAMETER='NLS_DATE_FORMAT';

PARAMETER                      VALUE
------------------------------ ----------------------------------------
NLS_DATE_FORMAT                DD.MM.RR

SQL> select to_Date(sysdate,'dd.mon.rr') from dual
  2  ;
select to_Date(sysdate,'dd.mon.rr') from dual
               *
ERROR at line 1:
ORA-01843: not a valid month
But when I do it this way, it works (looks like 'mm' can read 'mon' format also)
Code:
SQL> alter session set nls_date_format='DD-MON-YY';

Session altered.

SQL> select to_date('07-JUL-03','dd.mm.yyyy') from dual;

TO_DATE('
---------
07-JUL-03
Then I did a little homework (RTFM) and found:
http://download-west.oracle.com/docs...elem.htm#35494