java.lang.ClassCastException: agk cannot be cast to afe
This is typically a sign of mixing code between mismatched versions. I.e. you have a mod that is not for this version of minecraft, or you have two mods that are not compatible.
I'm not good at reading the obfuscated stack traces [so I could be completely wrong], but in 1.3.2 code the stack trace appears to be trying to merge two chest blocks to create a double wide chest. But one of the blocks appears to be a Leaf block and so not surprisingly the code is saying that a BlockLeaf (agk) is not a BlockChest (afe)
If you're not running any mods, then there's no reason not to force update and make sure that your jar is clean.. you should do that.
I did have trees growing near a single chest placed up high, which did disappear on me. It is possible that it happened at the time of the crash, as you described.
https://docs.google.com/open?id=0B8d1YZ_OATWoa0gwV1pKQURBRlU
Wasn't doing anything strange, just excavating stone and placing down dirt.
This is typically a sign of mixing code between mismatched versions. I.e. you have a mod that is not for this version of minecraft, or you have two mods that are not compatible.
I used to use to run MCPatcher for higher res textures, but haven't done that since 1.0.
If you're not running any mods, then there's no reason not to force update and make sure that your jar is clean.. you should do that.