Starting July 30th, you will no longer be able to log in to a Curse account that was not merged with a Twitch account. If you have not yet merged your Curse account with a Twitch account, please do so here! Otherwise, your account and its content will be inaccessible.
SIDE NOTE: If you are using MultiMC just add the Zyga.7.zip as a jar mod and you have to add the sounds into the instance you are using. If you are using a normal .minecraft with a bin folder and stuff you just open your beta 1.7.3 minecraft.jar with winrar or 7-zip and drag all of the files from Zyga.7.zip into the jar and put the resources folder from sounds.zip in your .minecraft. If this is to difficult for you to understand, then I honestly think you shouldn't be modding old minecraft anyways. Sorry.