Oracle Data Pump Exports and the TOAD Data Pump Wizard Exports, both create a .dmp file. When attempting to open one of those (Oracle 10g Data Pump export) .dmp files with the TOAD Export File Browser, the following error is displayed
"This is not a valid export file - please select another file"
The reason is that the data pump engine generates files that are not compatible with the old import/export utilities.
This also means that the Toad Export File browser cannot be used to open or review data pump generated export files.
Enhancement request CR56992 and ST116438 has been submitted to Development for consideration in a future release of Toad for Oracle.