i made a form with attachmentbox and i can't use every type of file. what are the types?

You can specify any file type you want through the software. Click click on the upload file element and then to the Properties tab. Here you specify what file extensions that are allowed.

When a website visitor uses my (s-drive hosted) form and attaches a Word document for upload, where does the upload go so I can retrieve it? I've got "save to server" check marked.

It goes to your "Forms" tab on the S-Drive Dashboard.
At the top of this page run your mouse over "S-Drive" now select "Web Forms".
Next click on the form you want to get the upload from.
Under the submitted on click the date and time that the file you want was submitted.

Thank you for the help with this; this is exactly what I was looking for!

Another related question - is there a way to download ALL the uploaded/submitted files at once?

Thanks!!!

Try clicking on the small triangle in the lower right on the form you want to work with on the forms overview page of your S-drive account. Then select See Results. This will show you all the entries for that form. Now select Download All from the drop down select to the lower left below the form results. Then click on Go