That is not an After Effects warning.
Are you using a third-party plug-in that tries to use the GPU?
Reinstalling my graphics drivers seemed to solve the problem... I should wait until posting, to make sure I don't solve the issue myself. xD
I get the same errors after Windows 10 has updated himself to a "newer" Windows 10. Tried to reinstall the most current Nvidia drivers, and it worked... for some time. Now i got the same error in AE and in PR while applying Warp stabilizer.
The most stupid thing that it happens during render sometimes. You put a long sequence to render, go to have a meal break,
and after 40 minutes there is a OpenCL "OK" message surprise is waiting for you at 5% of the render
This error happens of both of my machines, on the old one i5, GTX660 2GB and the new one i7, GTX1070 8GB.
Both have 16gb of RAM.