SUS Server Not working

Hi,
I have a network of two servers.
1. win2003server --- DC
2. Win2000 server Sp4 --- ADC

SUS server is running on win2000 server and i am using group policy to
update clients. My clients are not getting updated. Server synchronization is
ok. I had approved the updates. There is no error in windowsupdate.log.
Client used to query SUS server at the time set in Policy for updates. It
seems it diid'nt find any update.

SUS used to work fine earlier. Actually, we have changed our setup some
times before. The win2000server where SUS is working was a different domain.
We have reinstalled the Active Directory and make it an ADC.
IS this change is the reason of problem?

I am able to open SUSadmin on that server. But if i go to IIS Management. I
am not able to browse the Virtual Directory of selfupdate and content. It
says directory listing denied. Same error is coming in Default web site. But
SUSAdmin used to work fine. I have checked the Directory security and IUSR
account.

Any clue to diagnose the problem?

Thanks...Vineet