Microsoft’s KB article on it
Applying update to a clustered RMS
If the install fails and you need to run it again, this is where it installs it (on an x64 system)
C:Program Files (x86)System Center 2007 R2 Hotfix Utility
If the install fails and you need to run it again, this is where it installs it (on a 32bit system)
C:Program FilesSystem Center 2007 R2 Hotfix Utility