Trying to install SQL Server 2008 on a non English OS and setup is being blocked by this rule, however looking to performance counters everything looks fine. On Operating Systems pt-PT (Portuguese) setups is trying to look for HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Perflib\016 which don’t exist, setup should be looking for HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Perflib\0816 (0816 is LCID code for Portuguese, 009 is LCID code for English OS).
This problem is currently being corrected and should be available soon a correction. In the meantime workaround is quite simple, export HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Perflib\0816 to *.reg file, rename all entries of 0816 by 016 and import it again to registry, rerun SQL Server 2008 setup successful and finally remove ghost folder 016.
As soon more I have more updates about correction that is being implemented I will update this blog entry.