You may want to check the filesize parameter.
Even though Tahiti says that no action is required for the error.

Code:
IMP-00046 using FILESIZE value from export file of string

Cause: Either you did not specify the FILESIZE parameter in your
IMPORT command, or you specified FILESIZE=0 and the export file was 
created with a non-zero value for FILESIZE. Import will use the value
specified in the export file.

Action: No action required.