use CGI qw(:all);
use Net::FTP;

$file2 = upload('T3') or stufferror(); # Upload() returns a filehandle. stufferror() isn't executed at all.

# some more stuff goes here (FTP connection established)

$ftp->put_unique($file2,'stuff.txt') or uploaderror(); # this error is executed. It says 'Bad File descriptor'.

# rest of stuff