This crash occurs both when I apply a resource pack, and when I remove it.

Running version 2.3.13 on Minecraft 1.8.9

Here is the crash report.

i tried to recreate your bug, but was unable to do so.

does this crash always happen if you change resourcepack?

acording to the log you send me something isn't right in the blockregistry, so probably a mod isnt doing things right.

lastly i couldnt find the mod SpongeRecipe anywhere, so this wasnt in my test.

you could try removing mods 1 by one and try to recreat the bug so we can pinpoint if it's a compatibility error somewhere.

I deleted my entire .minecraft folder, regenerated and reinstalled forge, and the problem went away.

Thank you for your help

Edit:

I take it back, it has returned. Here is the crash log.

It is happening consistently. Previously (Before I purged my .minecraft folder) it happened every time, both singleplayer and multiplayer. Now, it's only happening on my multiplayer server. It's running all the same mods as I have in my client. (Excluding client side mods) SpongeRecipe is a custom mod which only adds a single recipe, I don't see how it would be causing the issue.

I'm also now getting a different error, seen here.

It would be very difficult to remove mods one at a time on the server. Since it isn't happening in singleplayer now, it doesn't seem like it would be a conflict, but if that's the only option let me know and I'll go ahead and try.

could you send me the full logs?

the error report makes no sense. the places that throw a error on those logs are kind of imposible.

I apologize, the log is obnoxiously long, too long for pastebin.
fml-client-latest.txt

Though it may be redundant, here is the corresponding crash log.
http://hastebin.com/akezotatoy.vhdl

The above is with other mods installed. Here is one with just Mapwriter.
fml-client-latest.txt

http://hastebin.com/dorivijodi.vhdl

i have to be honest here, i have no idea what's going wrong. and my best bet would be to see if a other mod is causing this.

you could try if you also get this error with a new server (create 1 localy or something)

I removed all mods, deleted all mapwriter config and map files and tested. The error still occurs in my older singleplayer worlds, but not in newly generated ones.

Either way, I'm moving to 1.9 and the issue doesn't seem to persist there. Thanks for the assistance.

my best guess is then that it has something to do with remapping id's on older world. and that forge somehow fixed this over time.

oooh well i will lock this then.

ps do tell me if you find any thing wrong with the 1.9 version.