I'm pretty certain that message just means that it has not found the V4.2 base figure files in the Runtime into which you are installing the morphs product. You get the same message when trying to install Aiko4 into a separate Runtime.

So the Q is - are you trying to install these morphs into the same Runtime as V4.2?

"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)