DW20 server crashes my minecraft when joining. (Console log provided)

I've been attempting to join my server after finally getting it up but there seems to be an issue that causes clients to crash when attempting to join my server. I'm seeing something about a blockentity id being skipped and so forth. Not sure what it really is and need help. Any help is appreciated! Thanks!

 

I don't use plugins such as bukkit or anything. Otherwise what kind of plugins do you mean?

 

I'm sorry. I'm not really sure where I can find these files. Could you tell me where to find them?

 

Hey, I think I may have temporarily fixed the issue. Thanks for the help though!