Just seen that addition to your OP,
The host of files.minecraftforge.net is having some hiccups this morning. Nothing that the Forge team can do for now.
This seems to be a thaumcraft related problem. Please report this to Azanor
As it seems you have a beta build this is a link to the thaumcraft beta issue tracker: https://github.com/Azanor/thaumcraft-beta