Checkout flow problem

Hi,

I am right now just creating a new online shop website, I decide to use a Hikashop starter version to try.


Everything is going well, except one thing:

When I test my online shopping, after everything is chosen in the check out flow, I click the next button, there should be a payment page or redirect to the ending page, but there is always a fault:
server error: 500
500 - Internal server error.
There is a problem with the resource you are looking for, and it cannot be displayed.

However, the order is created, all the information is there, when i choose paypal, i cannot get to the paypal page, when choose credit card, I can receive the card number though, just there is no page after the checkout flow, nothing after the next.

Can you help me with this?
This is really important.

Thanks!