Be more specific when you say "Any folder". Obviously, you're writing to "C:\Users" or you wouldn't be able to have a profile and logon. What folder are you talking about? It sounds like you're having a "User Account Control" moment to me.
Very good. Sorry to nitpick, but it's helpful to know the specific problem you're having.
Welcome to "User Account Control". The "C:\inetpub" folder is protected by default. You have a few choices:
Work with the files from an elevated process-- either from an elevated command-prompt, or an elevated instance of Windows Explorer. - Advantage: Seamless access to files and folders, no UAC prompts. Disadvantage: Rather a pain to start, UAC functionality lost and potential security risk.
Explicitly grant your user account access to the files. Disadvantage: You have to do it. UAC effectively disabled for that directory (potentially slight security risk, since a program you might run could modify c:\inetpub... files w/o asking for your consent).
Disable UAC. - Disadvantage: Potential security risk. You're back to running as an "Administrator" and any program you run can "own" the entire machine.
The "Advantage" to all of the above is seamless access to files and folders with no UAC prompts.