Sorry to hear about all the trouble with installing the runtime. In fact, due to major browsers having dropped support for native browser plug-ins recently, we are discontinuing the runtime at the end of this year, which is why it is no longer being maintained. There’s simply no point in continuing development on it when the major browsers will no longer run it.
The path forward for Panda3D in the browser is with the experimental WebGL port. The upcoming release of Panda3D will also have a new deployment system that no longer uses the Runtime in any form.
I admit we could be doing a better job at communicating this clearly. My apologies!