Bukkit

What steps will reproduce the problem?
1. Random occourance
2. NPCs stop talking to someone making them stuck in conversation
3.

What version of the product are you using?
Latest

Do you have an error log of what happened?

12:16:31 CONSOLE: [SEVERE] Could not pass event PlayerMoveEvent to QuestX v1.1.1
12:16:31 CONSOLE: [SEVERE] Could not pass event PlayerMoveEvent to QuestX v1.1.1
12:16:31 CONSOLE: [SEVERE] Could not pass event PlayerMoveEvent to QuestX v1.1.1
12:16:31 CONSOLE: [SEVERE] Could not pass event PlayerMoveEvent to QuestX v1.1.1
12:16:31 CONSOLE: [SEVERE] Could not pass event PlayerMoveEvent to QuestX v1.1.1
12:16:31 CONSOLE: [SEVERE] Could not pass event PlayerMoveEvent to QuestX v1.1.1
12:16:31 CONSOLE: [SEVERE] Could not pass event PlayerMoveEvent to QuestX v1.1.1
12:16:31 CONSOLE: [SEVERE] Could not pass event PlayerMoveEvent to QuestX v1.1.1
12:16:31 CONSOLE: [SEVERE] Could not pass event PlayerMoveEvent to QuestX v1.1.1
12:16:31 CONSOLE: [SEVERE] Could not pass event PlayerMoveEvent to QuestX v1.1.1
12:16:31 CONSOLE: [SEVERE] Could not pass event PlayerMoveEvent to QuestX v1.1.1
12:16:31 CONSOLE: [SEVERE] Could not pass event PlayerMoveEvent to QuestX v1.1.1
12:16:31 CONSOLE: [SEVERE] Could not pass event PlayerMoveEvent to QuestX v1.1.1
12:16:31 CONSOLE: [SEVERE] Could not pass event PlayerMoveEvent to QuestX v1.1.1
12:16:31 CONSOLE: [SEVERE] Could not pass event PlayerMoveEvent to QuestX v1.1.1
12:16:31 CONSOLE: [SEVERE] Could not pass event PlayerMoveEvent to QuestX v1.1.1
12:16:31 CONSOLE: [SEVERE] Could not pass event PlayerMoveEvent to QuestX v1.1.1
12:16:31 CONSOLE: [SEVERE] Could not pass event PlayerMoveEvent to QuestX v1.1.1
12:16:31 CONSOLE: [SEVERE] Could not pass event PlayerMoveEvent to QuestX v1.1.1
12:16:31 CONSOLE: [SEVERE] Could not pass event PlayerMoveEvent to QuestX v1.1.1
12:16:31 CONSOLE: [SEVERE] Could not pass event PlayerMoveEvent to QuestX v1.1.1
12:16:31 CONSOLE: [SEVERE] Could not pass event PlayerMoveEvent to QuestX v1.1.1
12:16:31 CONSOLE: [SEVERE] Could not pass event PlayerMoveEvent to QuestX v1.1.1
12:16:31 CONSOLE: [SEVERE] Could not pass event PlayerMoveEvent to QuestX v1.1.1
12:16:31 CONSOLE: [SEVERE] Could not pass event PlayerMoveEvent to QuestX v1.1.1
12:16:31 CONSOLE: [SEVERE] Could not pass event PlayerMoveEvent to QuestX v1.1.1
12:16:31 CONSOLE: [SEVERE] Could not pass event PlayerMoveEvent to QuestX v1.1.1
12:16:31 CONSOLE: [SEVERE] Could not pass event PlayerMoveEvent to QuestX v1.1.1
12:16:31 CONSOLE: [SEVERE] Could not pass event PlayerMoveEvent to QuestX v1.1.1
12:16:31 CONSOLE: [SEVERE] Could not pass event PlayerMoveEvent to QuestX v1.1.1
12:16:31 CONSOLE: [SEVERE] Could not pass event PlayerMoveEvent to QuestX v1.1.1
12:16:31 CONSOLE: [SEVERE] Could not pass event PlayerMoveEvent to QuestX v1.1.1
12:16:31 CONSOLE: [SEVERE] Could not pass event PlayerMoveEvent to QuestX v1.1.1
12:16:31 CONSOLE: [SEVERE] Could not pass event PlayerMoveEvent to QuestX v1.1.1
12:16:31 CONSOLE: [SEVERE] Could not pass event PlayerMoveEvent to QuestX v1.1.1
12:16:31 CONSOLE: [SEVERE] Could not pass event PlayerMoveEvent to QuestX v1.1.1
12:16:31 CONSOLE: [SEVERE] Could not pass event PlayerMoveEvent to QuestX v1.1.1
12:16:31 CONSOLE: [SEVERE] Could not pass event PlayerMoveEvent to QuestX v1.1.1
12:16:31 CONSOLE: [SEVERE] Could not pass event PlayerMoveEvent to QuestX v1.1.1
12:16:31 CONSOLE: [SEVERE] Could not pass event PlayerMoveEvent to QuestX v1.1.1
12:16:31 CONSOLE: [SEVERE] Could not pass event PlayerMoveEvent to QuestX v1.1.1
12:16:31 CONSOLE: [SEVERE] Could not pass event PlayerMoveEvent to QuestX v1.1.1
12:16:31 CONSOLE: [SEVERE] Could not pass event PlayerMoveEvent to QuestX v1.1.1
12:16:31 CONSOLE: [SEVERE] Could not pass event PlayerMoveEvent to QuestX v1.1.1
12:16:31 CONSOLE: [SEVERE] Could not pass event PlayerMoveEvent to QuestX v1.1.1
12:16:31 CONSOLE: [SEVERE] Could not pass event PlayerMoveEvent to QuestX v1.1.1
12:16:31 CONSOLE: [SEVERE] Could not pass event PlayerMoveEvent to QuestX v1.1.1
12:16:31 CONSOLE: [SEVERE] Could not pass event PlayerMoveEvent to QuestX v1.1.1

Please provide any additional information below.
Please help! :(  A server restart fixes it but the owner of the server won't keep plugins that spam us like this :(

Ill try to look at the player move event code but there isn't an awful lot I can do unless you can help provide clear instructions on how to reproduce the problem. Also with the stack trace you posted right at the bottom of that trace there should be something which indicates line numbers and the error type. If you could get that for me it would help a lot.