Q: setting environment variables

Hello out there, I've a question about setting environment variables in a distributed environment. I'm running an application (4GL/RDS) on Server A which accesses a database on Server B. Both servers running ODS 7.23. When the app creates a report, I get the error "-28 No space left on device". I can see that /tmp grows to 100% before 4GL reports the error. Where do I have to set the PSORT_DBTEMP variable to set the desired filesystem with enough space? I've tried to set the variable on Server A, but that has no effect. Do I need to set the variable before starting Online via oninit? Thanks in advance ... Dirk Scheer