SQL & PL/SQL

I AM GENERATING .DMP FILE THROUGH PROCEDURE(UTL_FILE READ FROM A TABLE GENERATE A .DMP FILE)

CODE I AM USING BELOW

EG:
TEXT_FILE_NAME :='TEMP_'||NEST_TAB_SELECT(I).SEL_NETWORK_ELEMENT_ID_KEY||'.DMP';

THEN I AM TRYING TO IMPORT THIS FILE INTO THE TABLE(SAME DATABASE) THEN IT RETURN


IMP-00037: Character set marker unknown
IMP-00000: Import terminated unsuccessfully

HOW WILL I RESOLVE THIS ISSUE
CONTENT OF MY DMP FILE IS
=================================
FILE_NAME_ID_KEY,CALL_START_TIME,SERVED_MSISDN,NETWORK_ELEMENT_ID_KEY

FCDR11-8984_200511061040_200611061040.FCDR;1,06-NOV-06,21620348474,10013
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Message was edited by:
anutosh

Message was edited by:
anutosh