I have CS5, the basic suite, for Mac. I can't open InDesign documents sent to me which were created in CS5.5. What can I do next, that will cost me the least? Upgrade to CS5.5 and get a free upgrade to CS6? Upgrade to CS6? Try and upgrade the long list of Plug-ins it says I don't have in CS5 to open the document? Any words of wisdom welcome.