Straight from the DBI Docs:

With most drivers, placeholders can't be used for any element of 
a statement that would prevent the database server from validating 
the statement and creating a query execution plan for it. 
For example:

  "SELECT name, age FROM ?"         # wrong (will probably fail)
  "SELECT name, ?   FROM people"    # wrong (but may not 'fail')
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So you'll need to change your code to:

$sth = $dbh->prepare(qq~select $rating from FanRatings where Title = ?
+~) or die $DBI::errstr;
$sth->execute($filename) or die $DBI::errstr;
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