Can't import CSV – blank page

Everything goes perfectly well until I click on the “Do the import” button. It brings me to a blank page with no success or error message, only the import progress bar on top telling me I’m on the 5th step.

When I check the subscribers page, it’s empty as well (I’m beginning the mailing list with the imported emails and haven’t opened for opt-ins yet).

I’ve tried the patch provided at http://wordpress.org/support/topic/plugin-knews-multilingual-newsletters-import-csv-error?replies=4 to no avail. If I enable debugging on wp-config, it gives me an error similar to the one in that topic (Fatal error: Call to a member function get_mysql_date() on a non-object), but on line 864.

http://wordpress.org/extend/plugins/knews/