Error message when playing mp

[jowett110]

I was playing multiplayer when this came up

Crash in application version: 30621.2989

data\lib\units\extensions\inventory.dsf(-1): cant find member: stance_block in type <UE_ScriptExtension>

Renderer: normal
Physics : threaded

Is this somthing to do with multiplayer or is it somthing else.It has ot the highest patch on and the latest video driver
GPU: Nvidia geforce 8400GS

[ColinCJ]

This is a common game bug, and is repeated on many systems.
The next patch may fix.