U44.. update error http://forums.adobe.com/thread/1289956 may help
CS6 and earlier programs have not been tested and will not be updated to run on Mac El Capitan
-which means that you try to use CS6 and earlier at YOUR risk of having problems
-you may get CS6 and earlier programs to install and run, or you may not (some do, some don't)
Install CS5 on Mac 10.11 https://forums.adobe.com/thread/2003455 may help (also for other than CS5)
-also a TEMPORARY security change https://forums.adobe.com/thread/2039319
-and more on gatekeeper https://support.apple.com/en-au/HT202491
If none of the above helps, you are simply not going to be able to use After Effects with your operating system
After Effects CS6 actually has been tested with El Capitan as listed on this page: After Effects and Character Animator ready for Mac OS X v10.11 (El Capitan)
Talk with your IT people about getting AE updated to 11.0.4 so that it works on your system. You should definitely be able to update it.
Has there been a fix to the AE CS6 11.0.4 not running on OS X El Capitan 10.11.6?