[jurialmunkey]

Okay thanks to @sualfred sending me his portable version, I've tracked down the problem and found a fix.

The problem is that the "SublimeLinter-pyyaml" package has been depreciated and so needs to be installed manually.

Steps to Fix:

1. Open Command Palette (Ctrl+Shift+P)
   
2. Type Install to find "Package Control: Install Package" and hit Enter
   
3. Once Package Control opens, type "SublimeLinter-pyyaml" to find it and install
   
4. Repeat the steps to also install "SublimeLinter"