Cannot create timer job without missing file

I'm using the Administrator credentials and I'm getting the following error message when trying to install the script:

WARNING: "C:\windows\system32\SPBestWarmUp.xml" is missing. Cannot create timer job without missing file.

I've tried manually copying the script and xml, and I was prompted to confirm writing to C;\windows\system32 (even though I'm adminstrator). Perhaps that's the reason the script is unable to copy the files to c:\windows\system32

Cheers