Did not find an acceptable spawnpoint problem

[xoft]

I can't say much about the first error, I'd have to thoroughly check the code first for that. For the second behavior, I can give you an explanation for that: Each player gets their own spawnpoint (so that when they use a bed, their spawnpoint updates, but no-one else's). That "bed position" is set for the player when they first join the world to that world's spawnpoint *at that moment* (and you most likely had the world's spawnpoint set to the {0, 168, 0} one at that moment). So the "kill" command brings you to your last bed position (which is the bad coords), while the "spawn" command teleports you to the (current) world spawn position.

To fix this, either edit your player's INI file, or just use a bed.

Hope this cleared it up