What you do when something like that pops up, like during an installer, is you
Take Ownership of the folder or file - then click the box in the installer to try again.
You don't want to take ownership of all of C: though, so what you can do is place a dummy text file there, then rename it exactly as the problem file that can not be written. Take ownership of the dummy file (just for good measure). Now, the installer can overwrite it.
8 is a little different security-wise than previous operating systems, notably at root of drives like your example.
Adobe is famous for this issue when updating stuff like Reader, even on 7 and below.
You'll sometimes see similar errors pop up in other ways when trying to run software, like access violation, or 0x00000005. Sometimes, it's just a permission issue with some data it wants to access, crashing the software.
There are other advanced ways to give yourself (your Windows account) similar admin powers like 7 and below, using group policy editor.