I assume you have Poser 5 if you are running many runtimes.
I did'nt think you could have a number of runtimes with Poser 4 as it would just confuss it.Please tell me if i am wrong.
I just manual remove or add files to the runtime that i need for the project i am working on.But always leave the Geometries and texture files alone.

Elgyfo wrote;
Mine works fine. I have Poser on my laptop and a number of runtimes on an external hard drive. Many runtimes means faster Poser! I have split them into groups like SciFi, Fantasy, Animals, Scenery etc.