Umbraco on Windows 7 64-bit

I'm trying to install Umbraco CMS on Windows 7 64-bit and I get the following exception:

[HttpException (0x80004005): Could not load file or assembly 'ImageManipulation, Version=1.0.2105.41209, Culture=neutral, PublicKeyToken=null' or one of its dependencies. Failed to grant minimum permission required.

The application pool's trust mode is set to 'Full', all the user permissions are just as on other sites hosted on the same machine. I went through all relevant topics on Umbraco's forum, but all advices are about the trust level.

How do I fix this?

Bit specific for a usual SF question but HERE is a link to a forum post chain about this exact problem on the Umbraco web site - hopefully you'll find an answer in there, lots of others seem to have the same problem.