I think you could see an improvement, (I wasn't aware of the method you provided above), by setting AutoCommit to '0'. For example,

my $dbh = DBI->connect("dbi:SQLite:dbname=pedro.lite","","",
    {AutoCommit => 0}) or die "Can't connect";
[download]

Then at the end (or after 'x' amount of inserts), commit your inserts.

$dbh->commit() or die $dbh->errstr;

Chris