请大侠帮忙看下这个错误 ORA-24315

sys@ORCL>set autotrace on
ERROR:
ORA-24315: illegal attribute type
SP2-0619: Error while connecting
SP2-0611: Error enabling STATISTICS report
sys@ORCL>select count(*) from scott.dept;  COUNT(*)
----------
         4
Execution Plan
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Plan hash value: 3051237957--------------------------------------------------------------------
| Id  | Operation        | Name    | Rows  | Cost (%CPU)| Time     |
--------------------------------------------------------------------
|   0 | SELECT STATEMENT |         |     1 |     1   (0)| 00:00:01 |
|   1 |  SORT AGGREGATE  |         |     1 |            |          |
|   2 |   INDEX FULL SCAN| PK_DEPT |     4 |     1   (0)| 00:00:01 |
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