If you must restore from a system-level backup, you must ensure that database server is shut down, just as it was during the backup.
When restoring a multiplex database, you must shut down all the secondary servers as well as the write server.
Before restoring, review the table of contents of the backup to ensure that all files required for IQ are present. The list of files depends on your application.
In the case of the temporary dbspace files, ensure that files or raw devices are present with the correct file names (or symbolic links) and lengths. Contents of temporary dbspace files are irrelevant until the database restarts.