In one of our Joomla websites we have a banner section. I have about 5 clients and 10 different banners on the site, example:

test.com/banners/click5.html
test.com/banners/click8.html
test.com/banners/click10.html
test.com/banners/click13.html
test.com/banners/click16.html
test.com/banners/click19.html

My question is do they have a negative impact on Google because the page is cloaking the affiliate url? In my webmaster Tools google shows them as restricted by robots.txt which is fine but they keep appearing and sometimes have warnings next to them? Are these banners using a redirect google does not like? Should I just add a direct affiliate link to the banners instead of this banner redirect?

Any information or suggestions would be greatly appreciated.

Thanks