Errors using expdp with `flashback_time=systimestamp`
Just had a look at the documentation.

It says:


  You can specify the time in any format that the
  DBMS_FLASHBACK.ENABLE_AT_TIME procedure accepts


So SYSTIMESTAMP should actually work... Though the docs suggest you need to enclose the parameter in quotation marks. Try:

FLASHBACK_TIME="SYSTIMESTAMP"