With the module loaded in the appropriate modules folder on my dev site, I find that the Masquerade permissions show up just fine in the admin permissions page, and the module appears in the Administer => By Module page. The problem comes when I attempt to configure the module this way. Clicking on the "Configure permissions" link here, or from the "Get Help" page results in either a WSOD or a "Website Down" error. I feel the module is not interfacing correctly, but I'm not sure what's wrong. For what it's worth, the block to switch users does not show up, either. Any thoughts?