Trying to install the 1.2.2 profile, but getting this message when it is installing.

This is a generic error that occurs when Twitch's download servers are spotty.

That ID appears to refer to PlusTiC, which we do not (nor have we ever) used in our pack. All of that author's mods were expunged from CurseForge recently due to some kind of internet drama/malicious code.

If you are just downloading the pack, I would suggest attempting again a bit later to see if their servers want to cooperate. If you were trying to customize the pack, well, not sure what to tell you.