Hi there,
I have the same (or similar) issue here, camera freezing every now and then and the only solution seems to be to remove the battery.
To me it looks like an AF issue and it even seems that it was introduced with one of the FW upgrades 1.02 or 1.03. The error occurs extremely often when I use a remote trigger instead of the shutter button. When taking a picture the camera starts focussing (which by the way takes incredibly long now with the XF 16-55). Then suddenly it stops and the camera behaves like doing a long-time exposure (LED screen turning black, orange status LED on). There are two alternatives to solve this: either remove the batteries (power switch won't turn off the camera) or wait. After a minute or so the lense makes some focussing noises and the camera "comes back". Hate to say this but it seems that Fujifilm's production standards seem to have reached an all-time low...