I faced with that error during expdp&impdp process between 2 databases.
There was no any issue on expdp process. I copied those export files to new server. While I started to impdp command it fails those errors:
ORA-39097: Data Pump job encountered unexpected error -30094
ORA-39065: unexpected master process exception in DISPATCH
ORA-30094: failed to find the time zone data file for version 28 in $ORACLE_HOME/oracore/zoneinfo