text index error

Oracle9i Enterprise Edition Release 9.2.0.1.0 - Production
With the Partitioning, OLAP and Oracle Data Mining options
JServer Release 9.2.0.1.0 - Production

SQL> begin
  2  ctx_ddl.create_preference('my_lexer','chinese_vgram_lexer');
  3  end;
  4  /

PL/SQL successed

SQL> create index idx_credit_company_coname on credit_company(coname) indextype
is ctxsys.context parameters('lexer my_lexer');
create index idx_credit_company_coname on credit_company(coname) indextype is ct
xsys.context parameters('lexer my_lexer')


ORA-29855: failed in the execution of the ODCIINDEXINSERT routine ORA-20000: Oracle Text error
DRG-50857: oracle error in dreii0fsh
ORA-00600: internal error code, arguments: [kcbnew_3], [1], [], [], [], [], [], []
ORA-06512: at"CTXSYS.DRUE", line 157