Error after hitting "finish"

-- url of the page with the problem -- : www.ronan.com/products/shop-our-products
-- HikaShop version -- : Essential to Business
-- Joomla version -- : 1.5.22
-- PHP version -- : unsure
-- Browser(s) name and version -- : Mozilla - most recent
-- Error-message(debug-mod must be tuned on) -- : Error_message

Hello,
I tried doing a test checkout with my credit card. I created a 50 cent item so that I could do this and then selected free shipping at check out. I entered my correct credit card information, and then when I select "Finish," I get "An error occurred" at the top of my page. Since it's so vague, not sure where to troubleshoot. Please help See attache screenshot.

Thank you.

Hi,

Turn on the debug option of the plugin and that should display more information on the issue.