I am trying to set up my forums and page(s). When I click the little icon to "open page builder" it takes me to a 404 error.

 

I've searched on here for blocks and pages, and nothing comes up.

Are you logged in on the front-end with the same administrator user that you're using the in the ACP? As it will bring you to the front-end to manage these things, you will want to ensure you're logged in with the same user.

I only have 1 user account set up, so I must be. I haven't launched it yet, trying to get it all set up first.

Are you using friendly URLs? If yes, have you uploaded the htaccess file?
It seems that there's much more broken on your site than just the block manager.

Ugh, I don't know how I could have screwed this up so badly in just a few hours. Is there someone at invision who I can just hire to do this?

There is a Providers list where you can hire 3rd party developers for custom work: https://invisioncommunity.com/third-party/providers/

I'm on that list too. 🙂

5 minutes ago, Lisa Lightner said:

Ugh, I don't know how I could have screwed this up so badly in just a few hours. Is there someone at invision who I can just hire to do this?

We would need to look further into this for you, however the access details on file appear to be incorrect or missing. Could you please update these details by visiting your client area, selecting the relevant purchase, then clicking "Review/Update Access Information" under the "Stored Access Information" section. 

We look forward to further assisting you.