What is this database dump format? I have a file which I believed was an Oracle data dump, but Oracle refuses to import it:

There is a problem reading from the import files
ORA-39143
"C:\nm\data\THEFILE.dmp" may be an original export dump file


The Linux "file" utility says it is DBase 3, but I doubt this, because the records number is not realistic and DBase tools fail to load the file:

THEFILE.dmp: DBase 3 data file (1380929624 records)


Here is an hex dump of the beginning of the file:

0003 4501 5058 524f 3a54 3156 2e30 3230


Any idea what database format it could be?
As @a_horse_with_no_name says, it's a file created with the original export utility, i.e an exp command rather than expdp. You'll need to import it with the matching original import utility, using the imp command.