When I try to install Exposure 6 into Aperture, I get the following message.
This error is caused by faulty permissions in your Aperture plug-ins folder. It can be corrected by browsing to the correct folder, and adjusting your permissions. In order to reach the correct folder, you must browse into the User Library. To access it, please click on Finder, and select the "Go" option from the menubar, and Choose "Go to Folder" from that menu.
There are actually 2 library folders. One is located in Macintosh HD/Library, the other one is listed below. The one below is the one you need to browse to.
Copy and paste this into the window ~/Library/Application Support/Aperture/
In there, you will see a plug-ins folder. Right click or Ctrl-click on that Plug-ins folder and choose the "Get Info" option.
At the bottom of the Get Info window will be an area for permissions. You want to set everything in that window to "Read & Write", except for the user named "everyone".
Once you finish this, just run the installer again, and choose Aperture. It should install with no further errors.