When I click my Clickbank affiliate link in a CB Profit Poster table, I get the error: "No input file specified"

This is likely because of an "abnormal" permalink setting in your blog.

Check your permalinks Settings ==> Permalinks

your-blog.com/wp-admin/options-permalink.php

Make sure you have NOT specified anything like:

Custom structure: /index.php (a very common mistake that for some reason many Wordpress users make)

Also, if you still have your permalinks set to "Default", we recommend you change it to "Post name" and that should solve the problem (it's more Search-Engine friendly anyway)!