Hi,
This error indicates that PHP stopped the processing of the page because it reached the limits of its configuration (too much memory used, or too much time used). The simplest solution is to increase these limits via the php.ini setting file of PHP. You should talk to your hosting company about that.
A more convoluted solution would be to create a backup of your website with akeeba backup, restore it on your local computer with wamp installed, perform the installation there, create a backup of your local website with HikaShop on it, and restore it on your online server.