Thank you for using Bitnami.
It seems that the installation has wrong permissions. 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.
Apart from that, could you please let us know which extension you are trying to install and the process you followed to install it?