We were flying through the end until the server suddenly started crashing. I attached a couple of those crash logs, but the main cause seems to be:

java.lang.RuntimeException: We are asking a region for a chunk out of bound | 65 -34
[...]
Requested chunk : 65 -34
Region bounds : 48 -44 | 64 -28
[...]

So the chunk 65 ( ?) was requested from the region file (actually region file r.2.-2.mca), whereas that region only contains chunks up to 64 - which sounds like a classic for loop issue where you start counting at 0 but have a off-by-one error. We were able to teleport away from there quickly before the server crashes again every so often, but this should still be fixed.

Also, where is the Teddy Bear?