-25325: Errors checking compatibility of external and db data types. See Loader server log file for more information 

Explanation:

Error executing the Loader command for exporting data. In the command, for individual columns you can specify the external data type of the values in the data stream. This error message is only a summary of the error. The error messages -25315 and -25323 specify which column descriptions contain errors, and they are only listed in the log file.

User Response:

Correct the command and then re-execute it.