Minecraft Monster Spawner help

Hey everyone i just had a quick question. How would I be able to use monster spawners in my minecraft server? my server proporties says its on. Thank you

 

"/give <username> 52 1"

 

I've done that, I cant set the spawner down but it wont spawn

i ment i can set it down

EDIT by Moderator: merged posts, please use the edit button instead of double posting.

 

Have you got Essentials? If so, I believe these is a command to change the spawner type.

 

its not the spawner the problem is they wont spawn

 

jacks1820 is the difficulty peaceful? If not, perhaps another plugin is interfering?

 

Moved to correct section.

 

Certain mobs only spawn on certain surfaces (e.g., grass) and at certain light levels (e.g., bright or dark). What kind of spawner are you trying to use?

I think the rules are listed here: http://minecraft.gamepedia.com/Monster_Spawner (can't check if this is the right page, because it's blocked by our corporate firewall).

Also check if you're in a WorldGuard region which denies mob spawning (do /region info).