Hi,
Someone reported a similar error here:
www.hikashop.com/forum/checkout/903978-e...ot-shown/339463.html
That patch is included in the 4.5.0.
However, it seems to be somewhere else.
Ideally, could you activate the "debug system" setting of the Joomla configuration and reproduce the issue ? That will display an error message with more information, which will help us better understand the situation. Because I'm not able to reproduce the error when doing what you describe in your message with the 4.5.0