As I understand it, Collections contain references or links to the actual content files in the Runtime library. If you move the library to another location, you break the links. The Collections links themselves are stored in the main Poser Runtime/Libraries/Collections folder.

The only thing that bothers me about this explanation is that word "half" - I would expect none of them to work!

"If I were a shadow, I know I wouldn't like to be half of what I should be."
Mr Otsuka, the old black tomcat in Kafka on the Shore (Haruki Murakami)