Office 2011 for Mac and Office 2010 are no longer supported and not available for download if you no longer have media to download these versions.
Here's where you can enter those product keys. You'll see this error message if you enter a product key for a version of Office that isn't available for download from /setup. Sorry, we can't find this product key in our database (ERR_INVALID_TOKEN) or Sorry, we can't set up your account at the moment (ERR_MISSING_PARTNUMBER or ERR_PKPN_DETAILS_NOTFOUND)