When you try to install Microsoft URL Rewrite Module for IIS on Windows 7 beta or Windows Server 2008 R2 Beta, the installer may fail. To workaround that launch the installer from the elevated command prompt by using the following commands:
For x86:
msiexec /i rewrite_x86_rtw.msi /l* install.log NETFRAMEWORK35_SP_LEVEL=0
For x64:
msiexec /i rewrite_amd64_rtw.msi /l* install.log NETFRAMEWORK35_SP_LEVEL=0