There are three steps to this

1. add no-index tag 

2. add canonical tags

3. Add them to robots.txt with disallow mark

Wait for few days for changes to implement
Ignore / mark the 404 errors as fixed

There is a free extension for adding canonicals - http://www.fmeaddons.com/magento/seo-canonical-url-extension.html - this does handle the parameter issue very well