Oracle Message EXP-00039 - export file string must be on a disk

ERRORexport file string must be on a disk
CAUSEOn some platforms, export can read files from tape. This message is displayed if the first file in an export file set was on disk and you specified a tape device for a second or subsequent file.
ACTIONVerify that you have specified the correct file name for the export file. Remember that all export files can be either on disk or all files can be on tape, but not mixed both tape and disk.