That list also mentions a vanilla sheep, I think it's just the list of currently loaded entities.Yes its mystcraft, best way of doing this to see for definite is remove mystcraft from the mods folder boot it up see if it crashes if yes that's your issue. However i feel this one is a bit more complicated as it has elements of the portal gun mod embedded in it
EntityPedestal['entity.PortalGun.portal_entityapg.name'/8, l='MpServer', x=745.50, y=55.00, z=-103.50],
As well as some thaumcraft:
EntityGolemTallow['Tallow Golem'/9, l='MpServer', x=783.69, y=55.08, z=-107.75],
This could just be a glitch caused by the mods but more info is needed mate to get a better response.
That list also mentions a vanilla sheep, I think it's just the list of currently loaded entities.
Also, where do you get the idea that Mystcraft is causing this? I don't see any evidence of that.
So it's likely Mystcraft, that doesn't make it a certainty. You shouldn't blame errors on mods before you know what really caused them.This:
EntityBlock['unknown'/1841, l='MpServer', x=2147483647.00, y=2147483647.00, z=2147483647.00], EntityBlock['unknown'/1840, l='MpServer', x=2147483647.00, y=2147483647.00, z=2147483647.00], EntityBlock['unknown'/1843, l='MpServer', x=2147483647.00, y=2147483647.00, z=2147483647.00], EntityBlock['unknown'/1842, l='MpServer', x=2147483647.00, y=2147483647.00, z=2147483647.00], EntityBlock['unknown'/1836, l='MpServer', x=2147483647.00, y=2147483647.00, z=2147483647.00], EntityBlock['unknown'/1837, l='MpServer', x=2147483647.00, y=2147483647.00, z=2147483647.00], EntityBlock['unknown'/1838, l='MpServer', x=2147483647.00, y=2147483647.00, z=2147483647.00], EntityBlock['unknown'/1839, l='MpServer', x=2147483647.00, y=2147483647.00, z=2147483647.00],
Seen it many a time, in relation to mystcraft. Never the less we need more information before a proper diagnostic can be done.
So it's likely Mystcraft, that doesn't make it a certainty. You shouldn't blame errors on mods before you know what really caused them.
Going on the idea that it IS Mystcraft, those entities could be block damage caused by instability.