hi, i my server has the new bukkit build 1.3.1, im on 1.3.2 now, but i can start the server fine, when i try join it sudden errors appear in the chat box, would anyone have any idea how to fix this so i can join the server?

13:43:46 [SEVERE] Exception in thread "Connection #1 read thread"
13:43:46 [SEVERE] java.lang.NoSuchMethodError: org.bouncycastle.crypto.BufferedBlockCipher.a(ZLorg/bouncycastle/crypto/CipherParameters;)V
13:43:46 [SEVERE] at net.minecraft.server.MinecraftEncryption.a(SourceFile:148)
13:43:46 [SEVERE] at net.minecraft.server.MinecraftEncryption.a(SourceFile:157)
13:43:46 [SEVERE] at net.minecraft.server.NetworkManager.j(NetworkManager.java:305)
13:43:46 [SEVERE] at net.minecraft.server.NetworkManager.i(NetworkManager.java:206)
13:43:46 [SEVERE] at net.minecraft.server.NetworkManager.c(NetworkManager.java:331)
13:43:46 [SEVERE] at net.minecraft.server.NetworkReaderThread.run(SourceFile:93)