As silly as this may seem...
Does the index.php in your template folder have a mosLoadModules for 'banner'? I have not played with all the new 4.5.1 templates... but the one I have played with did not have mosLoadModules for 'banner'.
You may have to place <?php mosLoadModules ( 'banner' ); ?> somewhere on your template.
Then in look in Module Manager and make sure your banners are aiming to the correct 'position'. ae: banner, left, right...
Hope that helps you... happy mambling...
webmasterPETE
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