the code looks ok at a glance.
when you say it 'didn't work', is the file not being uploaded ?
Jason from WA gave me some debugging tips.
prevent the redirect by changing the page to an empty string, then go the the bindings panel and expand the WA Digital File pro Global Status group, add the debug info binding to the page
post back the results.
** JUST NOTICED ** , try taking the leading / from the uploadfolder path, i think this may be a problem