Our guide about how to install a plugin in Redmine is a bit different, can you take a look at it?
It's important to mention that Bitnami packages and configures already existing applications. We can only offer support and help on basic and most frequent application configurations. Always based on the default configuration or on our guides.
If you have installed a third party plugin or modified the application/server configuration, probably someone with more experience and knowledge about that specific tool can help you better than we can. In this case, it seems you installed the plugin correctly but the issue appears when using it. I just checked that the plugin is not supported in the latest versions of Redmine as you can see here:
We suggest you to post your question on the official support forums of the application to know how to solve this issue or the alternatives you have
Do not hesitate to write us back if you have any other questions about the Bitnami solution.