Nobody can tell you anything regarding the warning without exact system info or other technical details. That aside, you are simply launching the render-only version. Check your aliases and the program folder for the full thing.
Hey man, so I had the same issue when on a job. I realised that if I downloaded a free template from a trusted site, it would reset AE. Just make sure you open AE from the downloaded template, then you have complete control over AE.
when i open after effects it gives me a not enough memory error after i click okay it then goes to the render queue and wont let me start a new project or do anything but then re close the program??... its a macbook pro 2012 with 4g memory. just bought it.. but clearly its not powerful enough for even the smallest task of opening the program?
...and therein lies the problem. You barely have enough memory to keep both the OS and AE runing, to say nothing of any other open applications. Get 16 gigs.