Hi,
Without the error message we can't know what is your issue.
So you have to look for the PHP Fatal errors in your log (you can use the timestamp to find the messages related to your test).
Regards,
PS : Please understand that "latest" is not a valid version number. It can be right today but wrong tomorrow or in few days with the HikaShop 2.6.4 release.
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.