This won't work with your example, because the [pagination-tag](http://buildwithcraft.com/docs/templating/tags#paginate) only accepts an [ElementCriteriaModel](http://buildwithcraft.com/docs/templating/elementcriteriamodel), not an array of already fetched entries:

<!-- language: lang-twig -->

    {% paginate MyCriteria as PageSubset %}


See also: [What are the differences between an elementCriteriaModel and fetched elements?](http://craftcms.stackexchange.com/q/265/177)

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If I understand your code correctly, you want to get all entries which have an empty `series`-field? 

If so, you don't have to fetch all entries and check against it, you can just add this to the [ElementCriteriaModel](http://buildwithcraft.com/docs/templating/elementcriteriamodel):

<!-- language: lang-twig -->

    {% set MyCriteria = craft.entries.section('databytes').series(':empty:') %}

    {% paginate MyCriteria as entries %}
    ....
    {% endpaginate %}


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**Why does the pagination tag need a CriteriaModel?**

An ElementCriteriaModel can be compared to a sql query, it specifies what elements/entries to fetch (it sets the criteria). If you [treat your CriteriaModel as an array or append .first()](http://buildwithcraft.com/docs/templating/elementcriteriamodel#outputting-elements) it will fetch those entries and replace the results with the CriteriaModel.

The [pagination-tag](http://buildwithcraft.com/docs/templating/tags#paginate) needs a CriteriaModel (or "query") because it adds an offset (to the "query") depending on what page you are on, and then fetches the entries. - That's why the pagination-tag doesn't work with already fetched entries.