Batch API is setup in my module but it does not open batch window progress
your menu callback function is rhmtts_csvimport_page_default. This does not exist or currently does nothing.
Your form function rhmtts_csvimport_uploadform has this submit handler rhmtts_csvimport_uploadform_submit and it never calls or creates your batch function called rhmtts_batch_submit.


Your code is more or less all there I would:


use drupal_get_form as my hook_menu callback function and give it the name of my form function.
I would add my batch function onto the form submit handlers for my form as outlined here https://www.drupal.org/node/180528. Then it should all work.