What options should I adjust? In the Adjust tab of the options in system preferences, start by increasing number of photos (with the Fewer Photos -- Many slider), and see if your Mac can keep up. If you've bought it in the last year or two, it can probably handle moving this setting one notch to the right. If the animation gets jerky, you can try lowering image quality (Quality slider) to see if that helps. It's also fun to reduce the number of photos used.
I can't install my license! Step by step procedure, with screenshot, is here.
The Use iPhoto Library button doesn't work. This button only works if you have your iPhoto library in the usual place. If it's in a different place, you can still use the library, but you'll have to navigate to it using Choose Photo Folder... After selecting the iPhoto Library in Choose Photo Folder..., you may wish to click that button again and then select the Originals subfolder. That's what the automatic button does.
The Use iTunes Artwork button doesn't work. This button only works if you have your iTunes library in the usual place. If it's in a different place, you can still use the library, but you'll have to navigate to it using Choose Photo Folder... Choose the Album Artwork subfolder of the iTunes folder.
Can I use my Aperture library? You can select your Aperture 3 library in the Choose Photo Folder... dialog in the Options. Larger libraries (perhaps >10,000 masters and versions?) on slower machines may cause the screen saver to delay for a short time on startup; let me know if you notice an excessive delay. You can choose a subdirectory of the Previews directory to limit by year. Unfortunately, choosing specific projects or folders is not supported. As usual for using Aperture photos from other applications, high resolution previews must be turned on.
It doesn't work / I can't install it! Make sure you're downloading the zip file to your computer and unzipping yourself in the Finder (ie, turn off the "open safe files after downloading" option in Safari preferences). Also, if you still have a previous version of MovingPhotos3D on your computer, try deleting it from your Library/Screen Savers folder, or the system-wide /Library/Screen Savers folder that you can find on your main hard disk in the Finder, before installing the new one.
The animation is not smooth. If you get jerky animations, go to the Adjust tab of the options. You need to reduce the number of photos (Fewer Photos -- Many slider), quality, or number of photos moved at once (Move Few at Once -- Many slider). It can sometimes help to reduce the speed as well (Fast -- Slow slider).
My settings are not taking effect. If you change settings, such as choosing the photo folder, but then don't close the screen saver preferences, then your settings have not yet been saved. The small preview window and the Test button will work as expected, but if the real screen saver activates, it will use the previous settings. So, close the preferences when you're done, and use the Test button to run the screen saver before closing preferences.
I see a dinosaur!! The dinosaur image will show if you've selected a directory with no usable image files in it.
Strange flickering; two of the screen savers run at once. If you use the Test button to run the screen saver, but the screen saver was also previously set to start after a short time, you may find that the test saver continues to run while a second copy runs as well, with unpleasant flickering between the two. Or, you may find that the screen saver engine crashes and you are returned to system preferences with nothing running. I believe this is a bug in Snow Leopard. If you have your screen saver set to run automatically after a delay, I recommend that you avoid the Test button. You can always set up a "hot corner".
Will the license work with upgraded versions? Yes, the license is for all 1.X versions. I suppose someday I might do a dramatically new version 2.0 that would require the purchase of a new license, but not for a while if ever.
How do I uninstall? Go to Library/Screen Savers in Finder, and drag MovingPhotos3D.saver to the Trash. If you want to remove all traces (this is not necessary), go to Library/Preferences/ByHost, and drag com.davidmcnerney.MovingPhotos3D.blah to the Trash. If you installed a license, then you can go to Library/Application Support and trash the MovingPhotos3D folder as well.
Email support questions, problems, and feedback to movingphotos3d at gmail.com. If you have bought a license and are having problems, my top priority is to assist you. Don't worry, you will be taken care of. Remember we may be in different time zones, and definitely check your junk/spam folder if you don't hear back!