00:36:25 [WARNING] Task of 'Spout' generated an exception
java.lang.NoClassDefFoundError: net/minecraft/server/Packet17
at to.joe.vanish.sniffers.Sniffer17.checkPacket(Sniffer17.java:22)
at org.getspout.spout.packet.listener.PacketListeners.canSend(PacketListeners.java:70)
at org.getspout.spout.SpoutNetServerHandler.syncedSendPacket(SpoutNetServerHandler.java:572)
at org.getspout.spout.SpoutNetServerHandler.syncFlushPacketQueue(SpoutNetServerHandler.java:564)
at org.getspout.spout.SpoutNetServerHandler.syncFlushPacketQueue(SpoutNetServerHandler.java:557)
at org.getspout.spout.player.SpoutCraftPlayer.onTick(SpoutCraftPlayer.java:1162)
at org.getspout.spout.ServerTickTask.run(ServerTickTask.java:41)
at org.bukkit.craftbukkit.scheduler.CraftScheduler.mainThreadHeartbeat(CraftScheduler.java:137)
at net.minecraft.server.MinecraftServer.w(MinecraftServer.java:482)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:414)
at net.minecraft.server.ThreadServerApplication.run(SourceFile:457)
Caused by: java.lang.ClassNotFoundException: net.minecraft.server.Packet17
at java.net.URLClassLoader$1.run(Unknown Source)
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:36)
at org.bukkit.plugin.java.PluginClassLoader.findClass(PluginClassLoader.java:24)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
... 11 more

I was forwarded to you by Spout Dev who said
"ah sorry at to.joe.vanish.sniffers.Sniffer17.checkPacket(Sniffer17.java:22) < that's your problem
go talk to whoever makes that plugin"

You should consider updating VanishNoPacket to the latest version. ;)

i am.

Your above message is unclear, so: The errors you observed are not possible in the latest version. So you must be running an outdated version.

I was using and AM using the latest Version v1.8.5 [CB1534+]
And CB 1550
AND Spout LATEST dev build

1.8.5 does not have a file named Sniffer17, nor does it reference net/minecraft/server/Packet17

So you are definitely not running 1.8.5

To confirm this, I downloaded the plugin and ripped it to shreds to search. No such file.