Having trouble with Pixelmon

Let me start with saying this all started when I updated sponge from build 1869 to the latest version along with Forge.

The issue is that players cannot throw down their Pokemon and the console gets spammed with errors every time its tried.

The Log:
http://pastebin.com/e6zwSiVd

[Edit] Server works as it should again by downgrading only forge. Still wondering what is causing this?

Any help is greatly appreciated.

Ah I had the same issue, make sure you have the same version of forge and spongeforge and a compatible version of forge for pixelmon