For people trying to install the MSDN version of Microsoft Office Sharepoint Server 2007 on a Windows Server 2008, please use the SP1 (trial) version download from the Microsoft download site. The msdn version (without SP1) has an incompatibility issue with Windows Server 2008, which is solved by the SP1. In order to install MOSS on Windows Server 2008, just download the SP1 (trial) and register it using your license key.
http://www.microsoft.com/downloads/details.aspx?FamilyID=2e6e5a9c-ebf6-4f7f-8467-f4de6bd6b831&displaylang=en
"This is the x86 version of SharePoint Server 2007 Trial for Standard and Enterprise editions. The downloads on this page include the original release of SharePoint Server 2007 Trial (OfficeServer.exe) and the original release of SharePoint Server 2007 Trial with Service Pack 1 included (OfficeServerwithSP1.exe).
Note: In order to install SharePoint Server 2007 on Windows Server 2008 you have to install the version of SharePoint Server 2007 Trial with SP1."
Regards,
Nico