You appear to be under the mistaken impression that you are using DBI in your code. You are not. A DBI script would start out something like this

#!perl -w
use strict;
use DBI;
my $dsn = "some system DSN or DSN-less connection";
my $dbh = DBI->connect( 
    "dbi:ODBC:$dsn",'me','mypass',{RaiseError=>1}
);
# ...
[download]

Unless you have a very specific reason to use Win32::ODBC, use DBI instead - there is more documentation and a larger community to provide support.