list printer in directory and "printer I want isn't listed"

Hi there,

I am fully aware that this has been discussed many times everywhere, but I would like to know if I'm missing something really obvious or there's a problem in our domain waiting to explode.

Ok, so, as others have done:

1. add printers on server 2008
2. share AND list them in directory
3. win 7 client do Add a printer> networkprinters
4. NONE of those are listed on the Select a printer box
5. however, they can still search it by selecting the PrinterI want isn't listed link

I found numerous forums that talk about this, and this is one of them:
http://community.spiceworks.com/topic/144502-printer-not-showing-up-when-searching-for-network-printer

Unfortunately none worked.

but, strangely enough, one of the "accidentally added with wrong details" printer is listed!
I've checked all the settings via properties page and they're all the same!

I tried to add the same printer (same IP port) with the correct details (name/description/etc) with the following options set but still not working.
this eliminate any settings on the printer itself.

any idea?
also ... what is the correct way of adding a printer on the server itself?
use Add local or add a network one? - see attached image
perhaps this might play a role.

really appreciate everyone's advice!