As to 1: open the script in the script editor and select 'Server' in the compatibility box in the lower left corner. This will show you the script steps which are incompatible with server. If the entire script is server compatible, then you're good with just the server as far as the script is concerned.
As to 2: I am not sure but doubt it. While the script runs, that file needs to know the location of the database. Adding it to the server does not make it so. The thing to try here is to see that you test the script to run ccorrectly in a client (using server compatible steps) and get that running. In this you will probably see that importing is not server compatible (at least I seem to recall that there are some issues with that) or if it is that you will need to give the location of the source. For a server-run script the locations are very limited: (from memory, I think it is in the Server PDF documents) windows\temp and the data\documents folder in the FileMaker Server folder (in Program Files). Other locations can not be accessed by server, something to do with privileges IIRC.
I believe the Perform Script on Server script step in FM13 is the way to go. Perhaps the only way.
it would be if a server-script needs to be triggered from within a database-script, yes. If I understand things correctly, this is a Scheduled Script from the server itself, so it already runs on the server.
The Perform Script on Server treats the script like a Scheduled Server script. Server side scripting is intended for OS level scripting.
The server side scripting from Windows is, correct. I assumed however that this is the Scheduled Script function from within FileMaker Server, but reading back I am not sure that that is the case.
Dan, just to be clear: you will need FileMaker Server on the server machine. That is the setup I had in mind in my firs answer to you.
But to be sure; can you describe in more detail what it is you want to do? As to database, number of users, will they connect using copies of FileMaker, or using IWP/WebDirect or Custom Web Publishing?