As Jonathan mentioned you should indeed use a 301 redirect if it is a permanent redirect and a 302 redirect if it involves a page which is temporarily not available.
It does show the title tags so I think that solving the redirect issue would also solve your SEOmoz missing title tags issue.

If you changed the 302 to 301 and it still shows that your title tags are missing let us know and we'll try to help you identify and solve the problem.

Fabrizo, as far as I know Google Panda is now part of the standard Google algorithm and it won't be a periodic event anymore. Penguin still is though.

If your product pages are duplicate content according to Google try and see if you can do something about that instead of no-indexing it. Is there no way you can update the products so they display a more prominent description? I understand that manually it's not a possibility because there are way too much products for that to be an option.

I did notice that on a lot of your product pages you have a standard text: "This item includes: PDF (digital sheet music to print), Scorch files (for online playing, transposition and printing), Videos, MIDI and Mp3 audio files (including <a title="This item includes Mp3 music accompaniment files.">Mp3 music accompaniment files</a>)*
Genre: classical
Skill Level: medium"

Since this is basicly the only text on a lot of pages I think it's a big part of the problem. Maybe you can change this text so it looks different for every product?

Try tools like http://www.plagspotter.com/ to find the duplicate content and see which solution is best for your specific problem.

I hope i helped and if you need more help let me know

I agree that you shouldn't try to get search pages indexed.
Google loves clean URL's and "?course=starter" is not really a clean URL.

One of the reasons why Google doesn't like this is because it's not good for the user experience.
Nobody is gonna remember a url with ? and = in it.

My recommendation would definitely be to change the structure of the website that every recipe has it's own page and that these recipes are sorted into categories. Then you can still use the search function so that people will be able to search and they will find their recipes. Trying to get these pages higher in Google may help in some ways, but i think it will serve you better to focus on getting pages with a clean URL structure higher in Google.This should also improve your CTR (Click Through Rate) because people trust websites more if they understand the URL.

About the duplicate content issues. Search pages are not really meant to be indexed by search engines in my experience. I always no-index the search pages because of the possible duplicate content issues and they are custom pages which appear bases on what a user does. Not something i would want to get found on in the search engines.

I hope I helped, if anything is unclear or you need more advice or have a different question than please let me know.

Why would you want to no-index your product pages? They seem like the kind of pages you want to get found on.

There shouldn't be a problem between the amount of index pages VS no-index pages except you won't get found on the no-index ones. Product pages tend to be the kind of pages that you REALLY want to get found on.

I think you should rethink your strategy to recover from the penalties.
Try to find out where exactly the penalties came from and fix the errors in that area of our website.