Batch Create - Blank Page On Clicking Upload

I created .csv file from the test template file using Numbers. .csv is correctly formatted (viewed in text editor). When I click UPLOAD button I get blank page, no progress bar etc, URL reads:
http://securus-temp.us/wp-admin/network/admin.php?page=batch-create-menu&action=process
Working in Safari 7.0.4 Mac OS 10.9.3

Any ideas?