Some problem occured with the machine so i just reinstalled OS and everything else
Now on machine These things are running:
Windows 2003 ENT Ed.
ADS, DNS server, DHCP Server, RIS, File Server, & ISA 2004

After reinstallation and installing AD,DNS & DHCP I was able to edit the policies.
Well but just after installing the ISA i didnot check for it.
Now the same error i m geting "network path not found"

This is the first error entry in the Logs regarding this :

Windows cannot access the file gpt.ini for GPO CN={31B2F340-016D-11D2-945F-00C04FB984F9},CN=Policies,CN=System,DC=TestLab,DC=local. The file must be present at the location <\\TestLab.local\sysvol\TestLab.local\Policies\{31B2F340-016D-11D2-945F-00C04FB984F9}\gpt.ini>. (The network path was not found. ). Group Policy processing aborted.

I am manually trying to access the sysvol folder directly from the drive and it is accessible but if i try to access it as a share, by going to first \\TestLab.Local , where it shows sysvol as shared folder, but when i click on it it gives error :
"\\TestLab.Local\SYSVOL is not accessible. You might not have permission to use this network resource. Contact the administrator of this server to find out if you have access permissions."

What could be the problem with accessing the share.