From the report, there are three possible problems, all of which are related to Ars Magica 2.
1) The item wakebloom is causing problems because of its ID of 777, try making it lower with the config file.
2) Ars Magica 2 is attempting to render entities, Optifine probably changes how they are rendered and Ars Magica 2 doesn't know how to render the entity.
3) Ars Magica 2 is missing an MCversion annotation, try contacting the mod author.
1) The item wakebloom is causing problems because of its ID of 777, try making it lower with the config file.
2) Ars Magica 2 is attempting to render entities, Optifine probably changes how they are rendered and Ars Magica 2 doesn't know how to render the entity.
3) Ars Magica 2 is missing an MCversion annotation, try contacting the mod author.
Let's do some math.
1/3 = 0.333...
1/3 * 3 = 1
0.333... * 3 = 0.999...
1 = 0.999...
1 - 0.999... = 0.999... - 0.999...
0.0...1 = 0
0.0...1 * 10... = 0 * 10...
1 = 0