This is not possible with the current version 9. Server side scripts are restricted to script steps which are web compatible. Export data is not web compatible.
You need a client running all the time which triggers the script.
Thanks Jens. Te next question is whether a client and server can run simultaneously on the same host. This would be my preference to manage security concerns.
I'm not sure wether this is possible with actual versions. But it is anyway very bad practice. You need different machines for server and client.
Separate machines will be ideal but I have used the following method, running FileMaker client and server on a server machine (virtual actually.) My users are on network machines.
The server machine has a small FileMaker database program (A) which runs a script on startup. This script simply calls another script in the main database (B) that is running off the FileMaker server. I then scheduled a task using the Windows Control Panel>Scheduled Tasks to start program A on a schedule. When the time comes, it launches FileMaker locally on the server to run Program A. Program A executes the script in Program B. Oh...Program A runs the script and then uses "Quit Application" as a last step so the FileMaker client program closes after each run.
This is how I got around not being able to schedule scripts within a FileMaker database. Hope this helps.