Error displaying code block – [avia_codeblock_placeholder uid="0"]

Hi

I have one page that displays the contents of a “Thank You” page. This page has a Google Tag for conversion purposes that was added to a code block.

When I open the thank you page directly, it is all fine.
The problem is when the thank you page contents are displayed in other pages. I see the code:
[avia_codeblock_placeholder uid="0"]

Here is a sshot: http://dns.d.pr/caq7xX/5vQdp8RP

I am pulling up the thank you contents through Formidable Forms.

Any idea on how to fix this?
Many thanks