Hi,
This error indicates that there is not enough memory to process the whole page. So it's not about the disk space but the allowed use of the RAM on the server.
Increasing the memory_limit setting of your php.ini might be a solution.
Otherwise, reducing the number of elements displayed per page on the listing might be another solution.
Menu items are displayed by Joomla, not HikaShop. So if Joomla displays a menu item that you unpublished it's something to fix in Joomla. Probably the the menu is only trashed, not deleted, it could be that you need to flush the cache on your website, or something like that.