A few general issues lately that have been bugging me. These are simple fixes right??

So a few things have been bugging me lately about my server.

It's on 1.6.2.
Some behaviors:
1. Slime just picks a player up and takes them for a ride in the sky, they do not let go until they've fallen and killed themselves after the oh so many smaller and smaller versions. It is very annoying. I do not believe this is Vanilla MC behavior, correct? How do I fix this?

2. Lapis Lazuli? blocks make a player bounce, I'm not sure if this is default behavior, I feel like it's not, but it's been a while since I really ran Vanilla MC.

3. Just tried a recent adventure map. Command blocks are cool! However, after loading a map, it changed a bunch of my gamerules? I manually set them back, at least the one it states to be changing in chat. The scoreboard is still there! How do I get rid of this? ahhh


4. I cannot place commandblocks on my server. I can edit, but not place. This may be a more common issue.


Ok so my plugins are very basic:
Commandbin
Multiverse-Core
Multiverse-NetherPortals
PermissionsBukkit
WorldEdit
RemoteToolkit Plugin

I'm compiling these as it's been a while I've tried to really tweak my server, and I feel like these have to have simple answers or solutions or at least explanations. =P