Problem to install FP 4 (folder unknow)

I have a problem when I try to install FP4 on 2 of my Notes server.

It say that i cannot find my folder

and in program line and database it give me “NULL” an dsay that i will install on default program folder.

Why can it not se the folders where the lotus domino is install.

On other server I don.t have the probelem.