Sometimes to open files with YAPI you will need to give YAPI access to read and/or write/modify/delete files. This is where the error message comes in. "Error:5" means that in order to open the file you'll need the elevated permission of a local administrator to take ownership and gain access.

You may already be logged on your system as a user that is a member of the local administrators, however Vista, Windows 7, and Windows Server 2008 offer additional layers of Security to help protect your system. This is called User Access Control. Basically even though you're on as administrator Windows protects certain administrative functions with another security layer. 

In order to Elevate YAPI so it can read and/or write/modify/delete files:

  1. Open the Tools application in YAPI, the toolbox icon
  2. Select Administrative Tools from the drop down menu
  3. Select Utilities from the drop down menu
  4. Find and select Toggle Elevation (Make sure the message says YAPI has NO elevated permissions. would you like to enable elevation)
  5. Select Yes 
  6. After the terminal appears you can close YAPI. When you reopen YAPI it will be elevated