Making a basic block in Drupal 6
The code you are using above is for Drupal 7, not Drupal 6. In Drupal 6, it would be the following one.

function blue_block($op = 'list', $delta = 0, $edit = array()) {
  switch ($op) {
    case 'list':
      // code from your blue_block_info()

    case 'view':
      // code from your blue_block_view()

  }
}