Regular export/import (exp/imp) utilities are different from DataPump expdp/impdp
utilities. The dump written by regular export/import (written with exp/imp utility) cannot be handled by DataPump import (expdp/impdp utility).
ORA-39000: bad dump file specification
Cause: The user specified a dump file that could not be used in the current job.
Action: Specify a dump file that is usable for the job.
ORA-31640: unable to open dump file "string" for read
Cause: Import was unable to open the export file for reading.
Action: Take appropriate action to restore the device.
From the error messages it is clear that Datapump is not able to read the dump file.
Use the regular import (imp utility - not the 10g IMDP) version 10g (10.2) to read the export dump written by exp utility version 8i.
Dump files generated by the Data Pump Export utility are not compatible with dump files generated by the original Export utility. Therefore, files generated by the original Export (exp) utility cannot be imported with the Data Pump Import (impdp) utility.
You could also refer to metalink note 132904.1 which has the Compatibility Matrix for Export & Import Between Different Oracle Versions.