You have the whole thing laid out in a tmpdir right? And the install fails but writes the packages to disk? Manually edit the tnsnames.ora file for the correct port, machine name etc. nsure that the oraenv contains the correct path to the tnsname.ora and all the other env stuff. I always liked to create an oraenv that I can source which contains everything the installer might want to know about then run it. Also check perms and ownership on the files it layed out.
thanx,
bill