I am not sure if other people had this problem as well, but my WOM client auto updated a few times recently. This was not a problem since it worked properly on its own, that is, until today.
Anyway, the fix is simple since all you have to do is replace your minecraft.jar file. I provide a link to the updated file below. This file needs to go into the “MineCraft\lib” folder. My prior file was over 2 megabytes while the new one is only 284 kilobytes.
I hope this helps someone.
https://s3.amazonaws.com/MinecraftDownload/classic/minecraft.jar