I use OtherDrops along with websend to create Items over my Webpage.

So, websend just issues the drop comand, and OtherDrops generates the Item(s).
Most of the Time it works just fine. But at seemingly random times, it crashes the Server. This is the Message I get when the Server Crashes:

[13:54:19] [Server thread/ERROR]: Encountered an unexpected exception
java.util.ConcurrentModificationException
at java.util.HashMap$HashIterator.nextEntry(HashMap.java:926) ~[?:1.7.0_45]
at java.util.HashMap$KeyIterator.next(HashMap.java:960) ~[?:1.7.0_45]
at net.minecraft.server.v1_7_R1.EntityTracker.updatePlayers(EntityTracker.java:152) ~[server.jar:git-Bukkit-1.7.2-R0.2-3-g530fcb7-b2982jnks]
at net.minecraft.server.v1_7_R1.MinecraftServer.u(MinecraftServer.java:646) ~[server.jar:git-Bukkit-1.7.2-R0.2-3-g530fcb7-b2982jnks]
at net.minecraft.server.v1_7_R1.DedicatedServer.u(DedicatedServer.java:250) ~[server.jar:git-Bukkit-1.7.2-R0.2-3-g530fcb7-b2982jnks]
at net.minecraft.server.v1_7_R1.MinecraftServer.t(MinecraftServer.java:545) ~[server.jar:git-Bukkit-1.7.2-R0.2-3-g530fcb7-b2982jnks]
at net.minecraft.server.v1_7_R1.MinecraftServer.run(MinecraftServer.java:457) [server.jar:git-Bukkit-1.7.2-R0.2-3-g530fcb7-b2982jnks]
at net.minecraft.server.v1_7_R1.ThreadServerApplication.run(SourceFile:617) [server.jar:git-Bukkit-1.7.2-R0.2-3-g530fcb7-b2982jnks]

The Command used is following like this:
"odd p:$username $item@$itemdata/$amount"

where of course $username, $item, $itemdata and $amount is replaced to the variables.

A Java Update fixed this.

Odd.. but if the Java update fixed it I'll close it for now.