查阅资料后，怀疑是11gR2的BUG。
Applies to:
Oracle Server - Standard Edition - Version: 10.1.0.3 to 11.1.0.7 - Release: 10.1 to 11.1
Information in this document applies to any platform.
DataPump Import Including Statistics Terminates With Fatal Error ORA-39126, ORA-6502, LPX-225 End-Element Tag "HIST_GRAM_LIST_ITEM" [ID 878626.1]
Symptoms
DataPump import terminates with the following errors captured in the import log:
ORA-39126: Worker unexpected fatal error in KUPW$WORKER.PUT_DDLS
[TABLE_STATISTICS]
ORA-06502: PL/SQL: numeric or value error
LPX-00225: end-element tag "HIST_GRAM_LIST_ITEM" does not match start-element tag
"EPVALUE"
ORA-06512: at "SYS.DBMS_SYS_ERROR"
ORA-06512: at "SYS.KUPW$WORKER"
Cause
The statistics included in the import may be malformed.
Solution
To work around this issue, repeat either the expdp task or the impdp task using the EXCLUDE=STATISTICS parameter. After import, regenerate the statistics for the imported objects on the target database using the DBMS_STATS package.
文档中未提及11GR2，但该版本上还是存在这个BUG的。
还是使用原来的expdp文件，在导入时，带上EXCLUDE=STATISTICS后，成功导入。