There are a number of articles out there about how to bulk-update permissions on calendars in Microsoft Exchange, most of them pointing to the PFDAVAdmin tool. The problem, though, is that you have to read the requirements for it very carefully. Case in point:
I ran in to this when trying to run the tool from my Server 2003 x64-based Exchange 2007 server. It happened again when I tried to run it from a Server 2008 x64 box, and from my Windows 7 x64 workstation.
As it turns out, PFDAVAdmin requires .Net Framework 1.1 to be installed. It isn’t recommended to install that directly on to your Exchange Server as it can cause issues with .Net 2.0, so I simply installed it on my Win7 x64 box, ignored the Compatibility Warning, and that was it – PFDAVAdmin worked perfectly.
