If you are unable to migrate your multiplex database following the procedures up to this point, try this alternate method.
Change your Sybase IQ 12.6/12.7 multiplex to a simplex (non-multiplex) database by dropping all query nodes.
Migrate the database to Sybase IQ 15.4 by following the steps for simplex databases only.
Recreate the multiplex by converting the simplex Sybase IQ 15.4 database to a multiplex, following the steps in “Converting Databases to Multiplex” in Using Sybase IQ Multiplex.