With the release of 3.5.2 a bug was found in Adobe InDesign CS5.5 for Win7 causing the Mag+ installer to fail. We are sorry for your trouble with this and hopefully Adobe will fix this bug or we will have to find a workaround. Meanwhile it is possible to install the Mag+ tools manually:
- Close InDesign
- Download and unpack this zip file (https://dl.dropbox.com/u/33037258/Mag%2B_CS5.5_win.zip)
- Place the folder under Programs
- Download and unpack this zip file (https://dl.dropbox.com/u/33037258/Mag%2BCS5.5_win_plugins.zip)
- Place the Mag+ folder inside your Adobe InDesign Plugins folder (most likely found under Programs > Adobe > Adobe InDesign > Plug-ins.
- Start InDesign and you should find the Mag+ plugin by clicking on Windows.