Mac Redstone timer crash

[fawnraper]

I am on direwolf20, and I made a system of pulverizer, furnace... which runs with 2 transposers connected to a redstone timer and counter. I'm not sure which is at fault, but when I right click on the timer, shutting down internal server. Here the crash log
crash-2013-02-24_15.18.26-server.txt

 

[Zexmaxwell001]

don't have a block in your hand. right clock it with an empty hand or a different tool.