I had the same issue as what Ericks17 reported at the beginning of this thread. Here's what fixed it for me.
I tried clearing the cache in recovery, and tried clearing the cache on several applications, nothing seemed to work. Then, From the Android Home Screen, I clicked on Menu, then System Settings. Next I went to Accounts & Sync. I Selected the gmail account that I had originally setup, and hit menu, and "Remove Account".
Once it was removed I went back and Re-Opened the Market. I was prompted to sign-in. I entered the same account details. When it authenticated to the market this time, I was then then be able to download the applications you were receiving errors for earlier.
I think the problem was (at least for me, possibly you too) that I didn't sign in right away because I have a horrible data signal in this building where I am working. So I need to hop on the guest wireless which requires that you hit a web browser to accept terms and conditions. I think manually create an e-mail account using my gmail credentials. When I opened the market, it asked me what account I'd like to use, I entered the same info, but it said that that gmail account already exists on my device. I believe that if I would have just been somewhere else when updated to this ICS Rom and had a data plan, and would have signed in from the beginning screen (authenticating to google's servers, and market) that my gmail account and market would have worked without issue. I may try it later just to see.
YMMV, hope this helps someone!
itnet7