• I suggest you put in error conditions in case the prepare_cached or the execute fails. You can get the database error message using  $dbh->errstr - it's often very helpful.
• Are you sure that you're finishing both of the statement handles? In the larger chunk of code above, there's only one finish.
• You could try doing bind_param separately from execute, in case the problem's there
• In answer to someone's question below, 'clockwork'. ;)

Hope that's even a bit helpful,

andy.