Thomas Lange wrote:
I'm using ...
- a 27´ mid 2011 iMac with OS X Yosemite 10.10.1, 2,7 GHz Intel Core i5, 16 GB 1333 MHz DDR3, AMD Radeon HD 6770M 512 MB
- After Effects CS6 Version 126.96.36.199
- mocha Version 2.6.2 build 4626
and according to the update-checker both programs are up-to-date.
Your software may be up to date, but your OS isn't though.
Updated to the newest version (10.10.3) now and there is still the same problem with the same error-message ...
You might see if the driver for your graphics card updated. Try a newer driver or try an older one.
Unfortunately I have no idea on how to update/check the driver for my graphics card and everything I can find online is "windows-only" - actually I can not even remember ever having updated my graphics card driver by hand.
A friend of mine has the same error and he uses Windows 8 with AMD-graphics as well. In his case a driver-update did not change anything and he is still not able to use mocha at all.
You might contact Mocha's tech support.
In particular older versions of mocha (current version is V4) do not support all file formats that AE supports.
I recommend that you convert your video to a jpeg or png image sequence or to a prores quicktime.