Sorry to revive this dead post, but, I had the same problem and I went on searching more.
The solution is to add if (event.state.getBlock() == Blocks.ice)
Since this link was the first link in a Google search I thought I would add on to it. Sorry again for reviving this dead post.
Same problem occurred.
Maybe deep Java issue.
Removed all of iChuns suite of mods:
-BackTools
-IChun
-Portal
-GraviGUn
-Hats
This is the error
http://pastebin.com/W5RXTR6n
Trying to launch a custom instance of modded minecraft; it's obviously not working. Actually it doesn't even finish loading minecraft to give me an error report, it just stops its progress.
http://pastebin.com/0qBdfFBR
I tried updating my java, it was current already.