Vista - Administrator without permission?

Hello,

Recently I've been running into an error of sorts that's been driving me
crazy.

I'm the administrator of my own PC, running Windows Vista, and occasionally
I'll get an error message in a number of programs, or just on my PC in
general, telling me I don't have permission to do this and that, and that I
need an admin to do it. Erm, why? When I'm the only admin...?

Please help if you can, this really doesn't make any sense to me and it's
limiting my access to my PC.

Thanks.

See my post under "Security" titled "Can't Access my Pictures and Music
folders".

I can access "Pictures" and "Music" when I open either from the Start menu,
but I get the message: "You don't currently have permission to access this
folder" when I try to open either folder from "Documents". I am the
Administrator for this Vista Home Premium installation. When I try to change
permissions I get the message: "An error occurred while applying security
information to: C:\Users\My Name\Documents\Pictures. Access is denied."