Tekkit Server Help error

[maved145]

ok So when i try to join my server, i get this error

[sEVERE] Encountered an unexpected exception NoClassDefFoundError

java.lang.NoClassDefFoundError: l

at a.<init>(CrashReport.java:27)

at a.a(CrashReport.java:319)

at net.minecraft.server.MinecraftServer.r(MinecraftServer.java:673)

at ho.r(DedicatedServer.java:270)

at net.minecraft.server.MinecraftServer.q(MinecraftServer.java:599)

at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:497)

at fy.run(SourceFile:849)

it will join for a second and then do that! ?

i have the server ftp so if any of you have any solutions that would be great thanks

[maved145]

Also when it comes up with the error the server stops and you have to restart it to get it working :/ ...