"convert file is invalid or incorrect version"
*Cause: An Oracle7 to Oracle8 convert file contains invalid data
or was created with an different version of the migration utility.
This error can also be caused by incorrect ORACLE_HOME environment
variable when ALTER DATABASE CONVERT command is issued.
*Action: Use a correct version of the convert file or regenerate it with
the migration utility. Make sure that the migration utility is the
same version as the Oracle8 RDBMS executable and that the
ORACLE_HOME environment variable is properly set.