Got Error 500 when adding to cart Magento 1

Question

I got 500 error when adding products to the shopping cart. I enabled the debug log and got the following error. I thought it may be caused by affiliate extension. So I disabled the module. But I still got this error.

Anyone can help me with this bug? I really appreciate!

Answer 1

Your module is disabled but it's helper is calling from this observer file:

app/code/local/MW/Credit/Model/Observer.php line no 399

Remove helper calling or remove this observer from app/code/local/MW/etc/config.xml then your issue would resolve