I was working with one of our Oracle 10g databases the other day when I tried to do an data pump export using the OEM.
It seemed to be doing it, but then spat out this error:
ORA-20204: User does not exist:
EXP ORA-06512: at "SYSMAN.MGMT_USER", line 122
ORA-06512: at "SYSMAN.MGMT_JOBS", line 139
ORA-06512: at "SYSMAN.MGMT_JOBS", line 78
ORA-06512: at line 1
The error has something to do with the permissions for the user you are logged in as when doing the export.
Continue reading Export Problems in 10g OEM