Why can't we have spiders?

I wanted to put my site on these forum directories for more easier access, but you need to put their link on your site for them to put your site on them. And after I add their link I give them they address where it's located, but they can't seem to verify it. It always says "link not found" I think it wont let their spider or whatever on the site.

are you sure you put it on correctly?

i had to do this with my .co.nr domin and it worked fine

although they havent realised my linkbak was taken off