I just answered ya bro...
Issue
This error is caused due to an unknown application making changes to the registry key pointing to the etc/services file that mental ray uses. The etc/services is the file telling the operating system which TCP port an application uses.
If the operating system (OS) cannot figure out where to locate the etc/services file, it cannot find out which TCP port to use when starting the mental ray service. The service then fails and signals this failure to the 3ds Max 8 installer; the error 1920 message is then displayed (which basically means the installer cannot install a service).
Solution
Important: Altering registry keys incorrectly may severely corrupt your OS and/or other software, which could possibly prevent your system from starting. Therefore, it is recommended that any modifications be made only if you are familiar with registry keys – use at your own risk.
Before you modify the registry, make sure to back up the registry and make sure that you understand how to restore the registry if a problem occurs. For additional information about backing up and restoring the registry, please refer to the following Microsoft knowledgebase article: http://support.microsoft.com/kb/256986/
1. You must be logged in to the system as an administrator in order to run the registry key fix: mrfix.zip
Download the attached file ‘mrfix.zip' to a temp folder
Extract the file 'mrfix.reg' using WinZip
Double-click ‘mrfix.reg’ to launch
If the installer fails with the same "Error 1920" message, please contact Autodesk Media and Entertainment Customer Support or your IT department for further technical assistance.
Advanced Use Only:
The registry key to fix is: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
Under this registry key, the DataBasePath value should be set to the following path: %SystemRoot%\System32\drivers\etc
The type of this value must also be "REG_EXPAND_SZ" in order for %SystemRoot% to be expanded to the correct windows installation folder (such as C:\windows)
Peace