eval { uploader( $dir, $name ) };
print "There was a problem uploading your file: $@" if ( $@ );

sub uploader {
    my ($upload_dir, $filename) = @_;
    ...
    open UPLOADFILE, ">$upload_dir/$filename"
        or die "Open for output failed on $upload_dir/$filename: $!";
    ...
    print UPLOADFILE ... or die "Output failed on $upload_dir/$filename: $!";
    ...
    close UPLOADFILE or die "Unable to close $upload_dir/$filename: $!";
    ...
}