Sometimes when you install Reporting Services 2005 on Vista (Beta) it often pops a error "Access to the path 'Global\CLR_RESERVED_MUTEX_NAME' is denied" when you browse to the Report Folders.
The resolution to this that I tried was pretty simple are own IISRESET, yes once you run this on the report server machine, things start working fine. I dont have the explanation as to why this happens but we get STARTED :).
Also following minimum set of IIS features that must be turned on for RS to install as the default install, help run the setup fine:
Common HTTP Features
IIS 6 WMI