Hi,
Please check the following link and let us know whether it helped.
http://service1.symantec.com/SUPPORT/ent-security.nsf/docid/2008031814120348
In MS-IIS manager, go to the properties of Default website
Click on Directory security tab
Click on Edit of “Authentication and Access control”
Check Enable Anonymous access (if unchecked) and replace username present with Domain Admin logged in and its respective password. In case of workgroup replace “user_name” with local administrator
Click on Edit of “IP Address and domain name restrictions”
Select the radio button “Denied”
Hit on “Add”, type in the IP address of local computer.(on which SEPM is installed)
Hit on Ok—Ok—OK
Restart MS-IIS service and reboot the computer