How is the 'updated' column in your table defined? Is it a datetime column or a text column? If it's a datetime column then you need to be sure that the date that you are giving it is in the right format.

This whole program would be a lot simpler if you used an ORM layer like DBIx::Class or a complete MVC framework like Catalyst.

But even if you don't switch to something like that, you should really look at using placeholders in your SQL statements as that will handle all of the quoting for you and remove some potential problems from your code.