No sound for Minecraft versions 1.6.x and forward

[Riff Raff]

Launcher Version: Build 374

Operating System: Windows 7 64x

Java Version: Version 7 Update 45

Antivirus Program: None

Description of Problem:

When I load up a pack that is on Minecraft version 1.6 and forward, all vanilla sounds are missing. I've tried using the vanilla pack in the launcher and the sounds are missing from all versions that are newer than 1.5.2 (which works fine).

Any sounds native to mods, like the morphing sound in morph, works just fine though.

Error Messages:

N/A

Error Log:

N/A

[Riff Raff]

some weird timeout caused a double post, sorry about that :/

[NRASean]

I'm getting the exact same thing.

Using the latest available launcher, Windows 7 x64 and Version 7 Update 45 x64.

All vanilla sounds are missing for all 1.6.4 modpacks. Older ones work fine. Also I am using avast antivirus.

Things ive tried:

+ updated sound drivers (RealTek rtkvhd64)

+ updated java (I'm running Version 7 Update 45 (64bit) (build 1.7.0_45-b18) on Windows 7 x64)

+ removed mods

+ copied vanilla assets folder into /modpack_folder/bin/assets/ and /modpack_folder/assets/

+ removed "slick-util.jar" from mods folder

Apparently sound works for my friend but not me

My forge/technic launcher log is here: https://gist.github.com/anonymous/7996812

Thanks