We can't know. We don't know what effects or footage is used in the project or how it's structured. This is most definitely a specifc effect having a hiccup, not a generic AE problem. And you misunderstand - your AMD card does support OpenGL, just not CUDA.
Thank you for the update Mylenium.
If I look at my display info, the card says OpenGL engine. Does this mean anything?
If it's not supported, then what's the point in purchasing a Mac If you cannot use AE's full capacity. Mac doesn't put Nvidia cards in there machines and on the Adobe website, ATI cards ate not listed; but in the same breath it says that most ATI cards that have come out in the past 5 years are supported. Surely Adobe and their technicians must have spoken with Mac technitions.
I am considering to buy the new Mac Pro; but am definitely going to change my mind if I cannot use AE's full compatibility. I don't see why spend so much cash if the cards aren't great.
Please could you then tell me what functions to switch off in the project file. I'll get the guy whom I bought the template from to switch of those functions.
Have a great day
Try rebooting your machine and see if the error persists.
The acceleration of which you speak is referring to an obsolete effect. The ray-traced renderer is really the only thing accelerated by the GPU in After Effects (well, some third-party plugins use it too, but they don't have to be on Adobe's list to work). Info on the GPU in AE here: GPU (CUDA, OpenGL) features in After Effects CS6 and After Effects CC
I called the ray-traced renderer obsolete because it has been superseded by the inclusion of Cinema 4D with After Effects - see here: details of CINEMA 4D integration with After Effects CC (12.0)
Were you able to create any exported video after rebooting? Let us know.