I just installed a trial version of Lightroom 4 for Mac today. But when I went to start it up, partways through the startup it stopped and a small window popped up that says: "This Beta version of Lightroom has expired. The application will now quit." What is going on?? I tried a couple more times to start it up again, but it just does the same thing. What is wrong with it, and can/how do I fix it??