As one poster already mentioned, the EULAS (End User Licence Agreements) you accept by installing this software are not very nice.
You now only allow DivX.inc to install Toolbars or some add-stuff (Adware), they also could check some details of your system and the installed sofware.
I’m not sure, if this stuff is already integrated or if the EULA is simply copied from the Windows installer, but it prevented me from installing the DivX package on my machine and I won’t install it on any machine I maintain.
It’s really sad, that they try to bug you with such a licence as they have a really nice product now.