Avast is blocking my Yahoo Nectar Toolbar download?

How can I stop it from doing this please?

I read elsewhere on this forum that this problem had been fixed, but it seems that this is no longer the case.

Please could someone also explain how to fill out the form about mistaken positives? I don’t really understand it.

Thank you.

What message do you get?..a screenshot would help

what is it about the form you dont understand?