Checkout issue - stuck at payment method

Hello, I'm new to opencart and I'm planning to use opencart on my upcoming website. I have a questions regarding about the checkout process and I hope someone has the answer for me.
While I was testing my opencart checkout process, I ran into an issue (or maybe a bug??) when I placed multiple items in the shopping cart. It did show up in the shopping cart but I can't checkout the items and I got stuck in step (5) Payment method. No matter what kind of method I choose it just won't process. Later, I realize it doesn't happen all the time, it only happens when I placed an item in the shopping cart and it doesn't show up under the main page Shopping cart section (not the link in the upper right hand corner but the one on top of the page).
Does anyone has this issue or is it just me? Does anyone has any ideas how I can fix this issue? By the way, I'm using Opencart v.1.5.1.3. Thank you!!

-Ian Z.

Found this link below. It resolved my issue, hopefully it'll be useful for someone too:

http://forum.opencart.com/viewtopic.php?f=121&t=52682