Server nullpointer exception

2014-02-18 21:20:19 [Info] [STDERR] java.lang.NullPointerException: Method [getP
eripheralAt] not found
2014-02-18 21:20:19 [Info] [STDERR]     at com.google.common.base.Preconditions.
checkNotNull(Preconditions.java:235)
2014-02-18 21:20:19 [Info] [STDERR]     at openmods.utils.ReflectionHelper.call(
ReflectionHelper.java:88)
2014-02-18 21:20:19 [Info] [STDERR]     at openmods.utils.ReflectionHelper.callS
tatic(ReflectionHelper.java:70)
2014-02-18 21:20:19 [Info] [STDERR]     at openperipheral.addons.peripheralproxy
.TileEntityPeripheralProxy.providePeripheral(TileEntityPeripheralProxy.java:24)
2014-02-18 21:20:19 [Info] [STDERR]     at openperipheral.adapter.AdapterManager
$1.getPeripheral(AdapterManager.java:32)
2014-02-18 21:20:19 [Info] [STDERR]     at dan200.computer.shared.BlockComputerB
ase.getPeripheralAt(BlockComputerBase.java:143)
2014-02-18 21:20:19 [Info] [STDERR]     at dan200.computer.shared.TileEntityCabl
e.getConnectedPeripheral(TileEntityCable.java:745)
2014-02-18 21:20:19 [Info] [STDERR]     at dan200.computer.shared.TileEntityCabl
e.togglePeripheralAccess(TileEntityCable.java:696)
2014-02-18 21:20:19 [Info] [STDERR]     at dan200.computer.shared.BlockCable.fun
c_71903_a(BlockCable.java:469)
2014-02-18 21:20:19 [Info] [STDERR]     at net.minecraft.item.ItemInWorldManager
.func_73078_a(ItemInWorldManager.java:421)
2014-02-18 21:20:19 [Info] [STDERR]     at net.minecraft.network.NetServerHandle
r.func_72472_a(NetServerHandler.java:556)
2014-02-18 21:20:19 [Info] [STDERR]     at net.minecraft.network.packet.Packet15
Place.func_73279_a(SourceFile:58)
2014-02-18 21:20:19 [Info] [STDERR]     at net.minecraft.network.TcpConnection.f
unc_74428_b(TcpConnection.java:462)
2014-02-18 21:20:19 [Info] [STDERR]     at net.minecraft.network.NetServerHandle
r.func_72570_d(NetServerHandler.java:141)
2014-02-18 21:20:19 [Info] [STDERR]     at net.minecraft.network.NetworkListenTh
read.func_71747_b(NetworkListenThread.java:54)
2014-02-18 21:20:19 [Info] [STDERR]     at net.minecraft.server.dedicated.Dedica
tedServerListenThread.func_71747_b(SourceFile:30)
2014-02-18 21:20:19 [Info] [STDERR]     at net.minecraft.server.MinecraftServer.
func_71190_q(MinecraftServer.java:691)
2014-02-18 21:20:19 [Info] [STDERR]     at net.minecraft.server.dedicated.Dedica
tedServer.func_71190_q(DedicatedServer.java:276)
2014-02-18 21:20:19 [Info] [STDERR]     at net.minecraft.server.MinecraftServer.
func_71217_p(MinecraftServer.java:587)
2014-02-18 21:20:19 [Info] [STDERR]     at net.minecraft.server.MinecraftServer.
run(MinecraftServer.java:484)
2014-02-18 21:20:19 [Info] [STDERR]     at net.minecraft.server.ThreadMinecraftS
erver.run(SourceFile:583)