When you define a Backup File Directory location on the External File Template\Input Tab\File Name-Path Options?  Or where an ‘backup oracle directory’ is defined - either in the application or elsewhere?  We have always a error:
ORA-29280: invalid directory path error
ORA-06512: à "SYS.UTL_FILE", line 270
ORA-06512: à "SYS.UTL_FILE", line 1243
ORA-06512: à "IFSAPP.EXT_FILE_SERVER_UTIL_API", line 474
ORA-06512: à "IFSAPP.EXT_FILE_SERVER_UTIL_API", line 483
ORA-06512: à "IFSAPP.EXTERNAL_FILE_UTILITY_API", line 5102
ORA-06512: à "IFSAPP.EXTERNAL_FILE_UTILITY_API", line 5153
ORA-06512: à "IFSAPP.EXTERNAL_FILE_UTILITY_API", line 5706
ORA-06512: à "IFSAPP.EXTERNAL_FILE_UTILITY_API", line 5725
ORA-06512: à line 1
ORA-06512: à "IFSAPP.TRANSACTION_SYS", line 1752
ORA-06512: à "IFSAPP.TRANSACTION_SYS", line 306
 ORA-06512: à "SYS.UTL_FILE", line 270
ORA-06512: à "SYS.UTL_FILE", line 1243
ORA-06512: à "IFSAPP.EXT_FILE_SERVER_UTIL_API", line 474
ORA-06512: à "IFSAPP.EXT_FILE_SERVER_UTIL_API", line 483
ORA-06512: à "IFSAPP.EXTERNAL_FILE_UTILITY_API", line 5102
ORA-06512: à "IFSAPP.EXTERNAL_FILE_UTILITY_API", line 5153
ORA-06512: à "IFSAPP.EXTERNAL_FILE_UTILITY_API", line 5706
ORA-06512: à "IFSAPP.EXTERNAL_FILE_UTILITY_API", line 5725
ORA-06512: à line 1
ORA-06512: à "IFSAPP.TRANSACTION_SYS", line 1752
ORA-06512: à "IFSAPP.TRANSACTION_SYS", line 306
ORA-06512: à "IFSAPP.TRANSACTION_SYS", line 886 
when the background job executes.  We we can't make it work this backup.