Could you please share with us the line you wrote in the config.php file? Apart from sharing the exact line you wrote, could you please run the following command:
ls -la /new/folder/you/want/to/use
We have a Support Tool that will gather relevant information for us to debug the issue. Could you please download and execute it on the machine where the stack is running by following the steps described in the guide below?
How to Run the Bitnami Support Tool
Please note that you need to paste the code outputted by the tool in your reply.