Thanks you for your report, I was able to reproduce the error or a slightly different one, when launching without the space age mod, while having rampantfixed and this mod + at least one of the dependency, i believe it's because my code for the "crazy mode" from this mod was active, and was attempting to attach some music from the other music mod to the planet Vulcanus ( or others) but those do not exist when space age is not active.
That was a mistake, it should have put all on Nauvis. It think it's fixed for the version 2.0.2. which should solve the problem, as i'm no longer able to reproduce it.
However i have no idea why rampantfixed was shown as accused of being responsible for the bug there, it feels clearly a mistake from me. So it is possible i have missed something.
Please let me know if there is still a problem !