are you sure the page is spiderable? check the robots.txt for the site. Otherwise just wait it out, the SEs will pick it up soon. PR can take 3 months to be updated publically.
I am not really sure what you mean by that, but I assume you are referring the link not being shown in Backlinks. Although Google indexes backlinks frequently, it takes a while for it to show on the Search with the Link operator. You should probably check in Webmaster Central and Yahoo Site Explorer. If it still doesn't show, wait for it to appear during the next backlin update.
Does the yahoo/msn shows backlink. If yes, then you got to be patient. Google will take time to consider the link
Google doesn't show all the links it finds, and I don't think Yahoo does either. So they may have found it, but just aren't showing it.
You can sign up in Google Webmaster Tools and find out if the link is counted or not, as they have included a new feature that shows all the backlinks to your site.
Google WebMaster Tools shows more of them, but I still don't think it shows all. Anyway, it's usually out of date with a time lag
I bought a PR8 link, its a strong site, PR is not fake, there is no 'no follow' and still the link is not listed in google backlinks. It shown up in Yahoo. The link is there for past 4 months. I hope I get advantage, I paid a lot of money for it.
which tool have you used to check your backlink? if you have used link:sitename.com , google will not show you all of the links
Why do you think it's not noticed?! also take care with buying a PR6 backlink, the link can actually be a PR0 ... google only update PR once 3 or 4 months, and it's updating for 1 or months before the updating date. So just that care. Some people only buy links to get nice PR after that they just drop the incoming-links. This can put you into troubles.
Can you all clearly put the urls you purchase such said urls so I can test out this nifty new buying links webmaster tool rat function so as to gain browny points and protect my adsense account? I think the twins are reading my blog and I am scarred I might lose my welfare Dollar or two a day.