If you're installing from zip files, as long as you have use folder names ticked there shouldn't be a problem except if you have the problem with freebies as karen1573 says. With Poser 5 you don't need multiple runtimes as it handles standard folder hierarchy much better. multiple runtimes is a throwback to P4 and isn't really necessary in P5

Injustice will be avenged.
Cofiwch Dryweryn.