robot.txt and page 404s

I create robot.txt :
"User-agent: *
Disallow: /admin/
Disallow: /system/
Disallow: /*&limit
Disallow: /*&sort
Disallow: /*?route=checkout/
Disallow: /*?route=account/
Disallow: /*?route=affiliate/
Sitemap: http://trangsucvaphukien.vn/index.php?r ... le_sitemap"
and webmaster notice error 404s:
HOw can I fix? Help me!!!

When did you add the robots.txt?

Did you manually clear the 404s afterwards and they came back?

I use seo pack pro, should I disalow limit and sort?
Error 404s in link limit and sort. How can I create page 404s? Or direct to home page?