This is probably obvious, but just in case as the installer doesn't say anything about it, the target folder you are expected to know to browse for is Poser (not Runtime). But if that's not the problem, and you are still intent on playing Poser 5 Roulette, I'm thinking that copying the SR4 exe into the Poser 5 folder first and executing it there will work. It appears to have been what the programmer who wrote the installer, and CL's QA dept(?), did.