Hi,
I've made a patch on these files. You can download again the install package of HikaShop 4.4.5 to get it.
However, without the full error message, it might not fix the problem.
The best when you have such an error is to activate the "debug system" setting of the Joomla configuration and then trying again to reproduce the issue. You'll get much more information on where the problem is coming from.