The first step to creating and rendering amazing fractals with Chaotica is to choose a distribution to install. This will primarily depend on your Operating System (OS), and there are versions for Windows, Mac OS and Linux.
If you plan to use Apophysis plugin DLLs, make sure the bitness of the plugin matches the bitness of the Chaotica .exe you are trying to use. Most plugins are 32bit, though some have been recompiled in 64bit.
Chaotica is available in both 32-bit and 64-bit versions for all platforms. Click here to go to the downloads page.