Looks like there’s a problem with the windows installer. We had an issue in one of the beta builds where even though you told it to use a different mysql port, it would still try to connect using the default port with the Bitnami credentials (obviously wouldn’t work with your already existing mysql installation.)
This issue was resolved in the Beta 4 build. Seems like it may have crept back in. I will bring this to the attention of the engineering team.