motion tile increases the size of a layer, and the error is telling you that it has made the layer too large to fit into the image buffer (the image buffer is a memory buffer that has to hold all layers in order to render a frame… if you’re a gamer, it’s similar to texture memory on a graphics card).
if it is occurring at a certain point in the render (say 100 frames in), the you might see if you can keyframe the motion tile setting at that point to decrease the size of that layer (or layers).
if you can’t, then you may need to try to split that layer up into smaller pieces and layer them out so they look like one layer. if they need to animate as a single piece, then you can parent them to a null and animate the null.
here’s an old link to some other tips for dealing with that error from generalspecialist.com (note, some may not apply to current versions of ae):
https://generalspecialist.com/2006/11/avoiding-the-after-effects-error-could-not-create-image-buffer.asp
Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW