en_sql_server_2008_enterprise_x86_x64_ia64_dvd_x14-89207.iso
(from MSDN) but not the contents of the x64
directory. So I think setup.exe
was seeing that only the x86
install files were available, trying to install those, and failing. The symptoms were exactly as described in the original question and the fix was to make sure the x64
directory had been extracted.