1. Did you restart the engine? In order to get the DBSPACTEMP variable accepted, you need to restart the engine. Once restarted, you will get a message in the online.log that the variable has changed.
If you restarted the engine, try with "SET EXPLAIN ON;" before executing the qry. You will get the qryplan, and it should include your temp dbspace.
If you display 'onstat -d', does your temporary dbspace contain a T flag?
2. Even with logged databases, IDS 9.30 has dynamic logging. It will create new log files on the fly, but only when needed. You don't know what log contains the oldest open transaction. The C flag will show you in what log it is currently writing. The L flag will show you in what log the latest checkpoint occurred.