Windows users, beware: the version of Colorama that shipped with AE 6.0 is buggy . It will let you choose presets, but other than that, you can't customize the output cycle.
To fix this error, download the Colorama update from Adobe.com, which comes with an updated Radial Blur filter (also buggy in the original release of AE 6.0). After downloading and unzipping the replacement plug-ins, drop them in the folder called Program Files\Adobe\After Effects 6.0\Support Files\Plug-ins\Standard and then restart After Effects.
Mac users, Colorama works fine as is, but you should also visit Adobe.com and pick up the latest patch, which fixes some other errors.
Mac update: http://www.adobe.com/support/downloads/product.jsp?product=13&platform=Macintosh
PC update: http://www.adobe.com/support/downloads/product.jsp?product=13&platform=Windows