Only web-compatible script steps will work when run by a server schedule - and that leaves out anything that interacts with the local file system, like exporting.
The reason it still works when you open the solution remotely is because you're opening it with the FMP client - which, unlike the FM server, has access to the local file system.
Thanks for the rapid response.
I was not aware of that limitation on scripts called from the server schedule. So I have no choice and will to continue to do such "daily housekeeping" using the installed FM client ...
Great answer, AndyFrazier!
To expand on that a bit for those viewing, you can check which script steps are web-compatible by going to Scripts > ScriptMaker > New (or edit an existing script). Down at the bottom left of the Script window, there is a check box for web compatibility. When you check this box, some script steps will appear gray. You will not be able to use a grayed out script step over the Web or in a Server side script.
Well, what I do is set up a machine to run those kinds of things for me. I use the Task Scheduler (in Windows; not sure what the Mac equivalent is) to open the file as a particular user. Then set a startup script that checks for that user (call it "ReportRunner" or something). If it's that user, rather than doing whatever the file normally does, it just goes and runs a bunch of reporting scripts, then quits. I do this on a regular machine, running the FileMaker client...so it can do anything a live user would do. I set this to run at night, so it's off-peak, and heavy reporting has some breathing room without slowing the whole system down.