Audacity Forum

There may be a problem with the "notch filter" Nyquest plugin zip file. After downloading to Windows XP Pro, attempts to open result in this error message: "The compressed (zipped) folder is invalid or corrupted."

Is there a way around this?

Probably just an error downloading it. Try downloading it again. You then need to unzip it into your Audacity plug-ins folder.
Where are you downloading from?