Well, what I should've mentioned is that I'm on Linux, which is why my directories have forward slashes in them (not backslashes). Now that I think about it, that's probably the problem right there: Linux users can create files with backslashes (\) in the name, which will cause problems for Windows users. And Windows users can create files with forward slashes (/) in the name, which will cause problems for Linux users.

I'm not sure about the Windows part though; could some Windows user please check if you can create a file with a forward slash (/) in the name? If not, maybe the problem is caused by Mac users, or maybe something else entirely.