I run the following from a machine name controller:

cd /home/client/test
/home/client/test> on -f vision pterm

and all is fine. But if I do

cd /net/controller/home/client/test (controller is the name of the local machine)
/net/controller/home/client/test > on -f vision pterm

I get "could not load library libphexlib.so.3".  libphexlib.so.3 is present on both machine ( controller and vision )

What I do not understand is why the error, but furthermore we have other systems that are configured in a similar 
fashion but work just fine and I can't explain why.