If you are going to use placeholders you might try prepare()ing and then executing queries rather than using do()

my $query = "UPDATE sometable SET someRecord=? WHERE otherRecord=?";
$sth = $dbh->prepare($query);
$sth->execute('value1','value2') or die $sth->errstr();
[download]

This seems to be the generally more accepted way of doing things if you are using placeholders.

Also I don't think you want single quotes around table and column names

Hope that helps
Chris