The SQL needs to be declared in the loop, as you're changing the variable $count each time. Consider the more idiomatic

foreach my $count (1..$tables) {
   my $sql =<<EOF;
....
EOF

    die ("Failed to insert row: " . DBI->errstr) if (!($dbh->do ($sql)
+));

}
[download]

Unfortunately you can't prepare and execute this statement with bound variables, as the table name is formed from one of the variables.