@TuNegocioRapido
It is possible that code you want to place there is incompatible or has some characters that cannot be saved.
No matter, you can place code also manually.
Open files:
oc-content/themes/tatiana/main.php
oc-content/themes/tatiana/search.php
oc-content/themes/tatiana/item.php
Find rows:
<?php echo osc_get_preference('banner_home', 'tatiana_theme'); ?>
</div>
<?php } ?>
<?php echo osc_get_preference('banner_search', 'tatiana_theme'); ?>
</div>
<?php } ?>
<?php echo osc_get_preference('banner_item', 'tatiana_theme'); ?>
</div>
<?php } ?>
Bellow these rows place your code for banner and save.