Make sure you're using the Campaign ID and not the Campaign Name in this field here:
You can find the ID by opening up the campaign in Pardot. With that open, take a look at the URL. You'll see something that looks like this:
The ID would be the number at the end, so in this example, you'd want to enter "811" in the Campaign ID field.
Custom fields using Radio Button, Checkbox, Dropdown or Multi-Select type are not supported by Pardot's API, so they are not available in Pardot actions at this time.
Pardot requires that you are an admin to perform certain actions. You can see permissions for your users here: https://pi.pardot.com/user
You'll need to upgrade your user's role to Admin, then reconnect the account to Zapier and try again.