add to cart button not working

[awalkersk8]

I have one Magento 1.9.2 installation and am currently setting up a second store to operate on the same installation, but from a different URL. 

The first store it is set so the customer must first register and be approved then, log in to see pricing and add to cart. In the second store I have removed this and can see the price and add to cart buttons, however when pressing add to cart it only works if logged in. If not logged in there will be no change to the cart and the error message "Cannot add the item to shopping cart." appears.

I've gone through so many files and google searches trying to fix this and all have been unsuccessful. I'm hoping someone can suggest something as I'm completely at a loss.

[Tom Robertshaw]

Is is an extension you're using to provide this functionality for the first store about not showing prices and needing to be an approved customer?

I'm wondering if disabling an admin setting in the second store view for this extension hasn't been enough to completely disable the modifications that it makes. Therefore leaving you in a situation where customers still need to be logged in on the second store to make purchases. 

What happens when you disable the module in the app/etc/modules/.. file for that custom extension and then try to add to cart in the second store?

[awalkersk8]

Hi Tom, thanks for the suggestion. I gave it a go, but no luck unfortunately.

I should probably mention, I have an extension installed (frontend configurable product matrix) that allows me to have different display options to enter quantities to add to cart. I'm using it for configurable products and it has either: add single product via a dropdown or add multiple via entering the quantity in a text box. While not logged in I can use the add multiple text box and it will add items into the cart, but the dropdown option does not. When logged in both work. Unfortunately the add multiple is not the option I want to use for the second store, due to the layout of it.

I have tried disabling this extension and using the standard dropdown, but it too has the same issue of needing to log in to add to cart (again it works when logged in). I've also tried using some of the original themes that haven't had any modification and they still have the same issue.

I feel like it could be some coding to do with the dropdown (however I'm just guessing), but I have looked everywhere in app/design/template/frontend  and the folders inside of that to find any code such as getCustomerSession as I had added some of that code when creating the original site.

Let me know if you have any other ideas. Any suggestions are much appreciated.