Fatal error

1)"Add to cart" button doesn't work.
2)When "Add to cart HTML link" on product page, it doesn't work and the following message displayed.
3)When "checkout layout" set on menu, it doesn't work and the following message displayed.

Fatal error: Allowed memory size of 33554432 bytes exhausted (tried to allocate ** bytes) in *********/public_html/libraries/joomla/database/database/mysql.php on line 462

Could you please advise me how to solve it?

Thank you for your prompt response.

the following is URL.

URL:www.emm-adult.com

First, you login.
user name "test", password "test"

Then you can find the tab for shopping site for right side of top menu.
It is HIKA shop system.

I would like to built-in shopping-cart system for "login user".
It is request of my client.

---

Afterwards, I faced the following phenomenon.

1)"Add to cart" button doesn't work. >> go to TOP page.
2)When "Add to cart HTML link" on product page, it doesn't work and the following message displayed.
>> When login "admin", the error happened. When login another account, templete is broken.

---

Thank you.

I set the option "After a product is added to the cart" to "Always go to the checkout" already.
But when I clicked "Add to cart" button, it doesn't work and go to top page.
So, I set the option to "stay and display pop up".
The pop up is displayed for about 2-5 second.
The Pop up is active and I can go to check out menu.
But themplete is broken.(see attached file)

*Only when I login as "admin", Fatal error is happened.