ORA-39126: Worker unexpected fatal error in KUPW-WORKER.PREPARE-DATA-IMP 71 ORA-06512: at "SYS.DBMS_SYS_ERROR", line ... ORA-06512: at "SYS.KUPW_WORKER", line ... ORA-xxxxx: underlying error message – that’s the real cause. 3.2 Identify Failing Table Search for Processing object lines just before the error:
If the error persists, contact Oracle Support with the full import log, dump file checksum, and parfile used. ORA-39126: Worker unexpected fatal error in KUPW-WORKER
grep -A 20 "ORA-39126" import.log Typical stack: line ... ORA-06512: at "SYS.KUPW_WORKER"