Game crashes when an empty file is in the Item-Set Folder of a Champion and this Champion is played

Steps to reproduce:

1. go to %LOLDIR%/Config/Champions/Jinx (or any other champion)
2. create a new Text document and don't give it any content (0kb)
3. Play Jinx (or the champion you picked)
4. In loading screen your game will crash

Since you normally don't do this, it shouldn't be a problem, however since there are many programs out there to download item sets it can occur due to a bug in one of this programs (that's what happened to me)