where it works locally, but not on the remote server, the extensions is configured properly, but you are running into a server setting that is causing the issue.
the most likely culprit is the php memory limit setting.
try adding the following at line 1:
if you are still having an issue, find the following line:
$WA_redirectURL = "artisti.php";
and change it to:
$WA_redirectURL = "";
to prevent the redirect. This code appears 3 times, change it in all 3 locations.
Then turn error reporting on using this code at line 1:
then from the bindings panel expand the Uploaded files Global Status binding group and add the Debug Info binding to the page.
post back the results.