I installed Kile on Mac OS X using Macports some time ago. The other day I installed homebrew and used it to install some software. After that, I get an error every time I try to build a document in Kile.

[PDFLaTeX] finished abruptly
File `article.cls’ not found. ^^M

I’m assuming homebrew messed with some of my paths? How do I fix this?

It looks like you need to reinstall Latex, as "article.cls" certainly sounds like a file which belongs to Latex.