What is the ERC (European Research Council)? Find more information here:

-ERC website
-Euresearch: the Swiss guide to European research & innovation

Q: Can I be a CoG panel member and apply for an AdG the same year?

Yes, you can. If you serve on a panel for a call, you are ineligible to apply for grants at the same level the year they serve on the panel, and two years after (when the same panel members will be sitting). However, they can apply to other levels of grants without any issue.