It's never a good idea to run an old version of WordPress, so I would recommend finding the source of the issues above all else. Old versions receive no security updates and have no long-term support, so by rolling back you're leaving yourself extremely vulnerable to security issues that have since been fixed.
To fix your current install of 3.3.1, check out Blackbox; it will help you find any errors. WP 3.3.1 is solid, so any issues would almost certainly be with the theme or plugins. Naturally, make sure both are up to date.
If you must roll back, first off, and I can't stress this enough, do a dry run on a test server first.
You'll want to remove all files except:
- Any customizations (of which there should be exactly zero)
Next, re-upload the old version (first removing the above from it so you don't overwrite anything). It's possible that some things in the database changed as well, so if nothing in your site has changed you could consider rolling that back too, but it's more likely than not that you won't have any trouble. Once you do this, WP will probably ask you if you want to update your database, and you should say yes. Again, do this on a test server first, and if it goes as you want, then do it live.