Installing MS Office SharePoint Server 2007 on Windows Server 2008 R2
Windows Server 2008 R2 is compatible only with Office SharePoint Server 2007 with Service Pack 2.
At a moment Microsoft have not released a version of MOSS with built in Service Pack 2.
So if you will try to install MOSS without service pack or with SP 1 you will get following error:
All what you need is to create own slip-streamed installation of SharePoint Server with Service Pack 2 included.
Microsoft have an official how-to create an installation source that includes software updates:
http://technet.microsoft.com/en-us/library/cc261890.aspx
After that you have possibility to install MOSS with SP2 on your Windows Server 2008 R2