After Effects warning: This project contains a reference to a missing effect.

hi , ( Good evening in my region ) 

To resolve the issue of the missing effect, you'll need to install the "Element" effect. If you don't have the Element plugin, you can download it from the Adobe official website or from a trusted source. You can also visit websites like https://dafont.style/ to search for fonts used in your project and install them on your computer. This way, you can address both the missing effect and font substitution issues.

Good morning (in my region)

It  would help to know whicht videohive template you are trying to use. That way we can check what effects are included there.

Because your CS6 version is nearly 10years old that could also be a problem - most of the templates on videohive require up-to-date software. And CS6 support is shut down since 2017.

About the font: Based on your text maybe wou're searching for this font: https://www.dafontfree.io/bahnschrift-font/

Cheers,
Gabs

It refers to Video CoPilot's Element 3D. Bahnschrift is a commercial font, which for Creative Cloud subscribers is available via Adobe Fonts. Otherwise you'll have to buy it from Fontshop.com or another such source or substitute it for a font you already have.

Mylenium

I would think the warning about Element is not related to Premiere Elements. Element is the name of the effect in After Effects.

Regarding to the font, is Bahnschrift necessary for your project? If not, you do not stick to using it. The substitition of the font is no problem to edit your project.