Loading settings fails (Access is denied) for domain accounts

I have installed Windows XP Pro SP3 in my system and i don't know why domain accounts are not having access to many files in the c:\Windows and c:\Program files folders. It says "cannot load a profile" . As far as i am aware the domain accounts are having administrative rights and access to the files but i get an error message saying "C:\windows\system32\wupdmgr.exe Windows cannot access the specified device, path, or file. You may not have the appropriate permissions to access the item." what might be wrong? Is there anyone who can help me out????

It seems as if you are having similar issue mentioned in the below thread:
Cannot load profile Event ID: 1500
If yes, than you can try out the solution that i have mentioned there. Post back if it helps or not, best of luck.