Item ID conflicts?

[Setari]

So I played Minecraft fine this morning, and upon getting home from work I tried to boot up DW20 FTB and here's what I got:

http://paste.ubuntu.com/1687103/

(pastebin doesn't work for me atm, sorry but it's the same thing)

So how do I fix this? Can I salvage my world or do I have to start another one?

 

[Norfgarb]

I'd say your world files should be ok, it looks more like something went wrong with installing the modpack, or you installed something like optifine over it which messed up some of the files.

Edit: So i'd say make a backup of your world and try reinstalling the modpack (without optifine or any other extras if you had any)

 

[Setari]

I had optifine but I removed it and in the modpack edit area it's not even in the mods anymore, which is weird because I just disabled it, not removed it entirely. But I did what you said so we'll see.

 

[Setari]

No, it still didn't work. The item ID conflicts are still there... any more ideas?

Also if I hit no for it to shut off, it gets stuck on 'Shutting down internal server'.