I opened up Brawlbox and it gave me the error.
(http://s5.postimg.org/wt403161j/asdfpaosdfpsodv.png)
I tried reinstalling BrawlBox, but it did not work. I do not know what exactly happened to Brawlbox. I did not do anything wrong with Brawlbox. It just crashed.
I use BrawlBox (v0.76b) (Hotfix 2).