I'm getting the same error on a project:
Originally created in CC/Mac, downconverted to CS6/PC (I don't yet have the exact version release).
The sequence is 10 layers deep, and throws this error if we try to preview. If 8 of the 10 layers are turned off, then the sequence will preview as normal.
So, is this a bug and is there a CS 6 version release that fixes this, or am I looking to reallocate RAM?
Thanks!