Categorizing Custom Posts via selected fields – 2

Hi, I am creating this ticket as a continuation to the previous – http://wp-types.com/forums/topic/categorizing-custom-posts-via-selected-fields/
For some reason, I cannot update new comments onto that, keeps asking me to log in.

Anyway, continuing from that ticket, I used the following code:

$my_field2a = explode(',', str_replace(' ', '', types_render_field("education-level-resource", array("output"=>"raw"))));

And error printed on page was:

1Array ( [0] => )

The post is still created, just it is not categorized to anything.