I am having the same issue as the above with the 2012 trial version of City Engine, single use and it says it is authorized - I am on my 4th re-install and have tried moving the install location to different folders where I know I have full access. I was originally saving it under C:\Program Files (x86)\ArcGIS\CityEngine (where I have read & execute, List Folder Content, and Read permissions) but recently installed it to my 'My Documents' (where I have Full Control). I have tried running as Admin and client, adding -Dogal to the CityEngine.ini file, starting and stopping both ArcGIS license manager and FlexNet Licensing services.
Looking for more ideas.