Hi, i am preparing for my 70-640 AD 2008 R2, 2nd edition and during the DNS Lab (DNS Delegation) i was able to create DNS delegation for the domain tree northwindtraders.com in SERVER10,but when i tried to create domain tree through the AD Installtion wizard on SERVER20 i was getting error "domain already exists" error and it failed with that, after further research i checked and made sure that SID's are different in tha both the servers SERVER10 and SERVER20 and tried it once again and this time i ended up with "Cannot create a turst with parent domain|" request not supported error and i tried it multiple times and i keep ending in same error.
Any help would be appreciated.